diff --git a/testing/web-platform/tests/common/dispatcher/README.md b/testing/web-platform/tests/common/dispatcher/README.md
new file mode 100644
index 0000000000000..befbb19ae9116
--- /dev/null
+++ b/testing/web-platform/tests/common/dispatcher/README.md
@@ -0,0 +1,33 @@
+# Message passing API
+
+`dispatcher.js` (and its server-side backend `dispatcher.py`) provides a
+universal queue-based message passing API.
+Each queue is identified by a UUID, and accessed via the following APIs:
+
+-   `send(uuid, message)` pushes a string `message` to the queue `uuid`.
+-   `receive(uuid)` pops the first item from the queue `uuid`.
+-   `showRequestHeaders(origin, uuid)` and
+    `cacheableShowRequestHeaders(origin, uuid)` return URLs, that push request
+    headers to the queue `uuid` upon fetching.
+
+It works cross-origin, and even access different browser context groups.
+
+Messages are queued, this means one doesn't need to wait for the receiver to
+listen, before sending the first message
+(but still need to wait for the resolution of the promise returned by `send()`
+to ensure the order between `send()`s).
+
+# Executor framework
+
+The message passing API can be used for sending arbitrary javascript to be
+evaluated in another page or worker (the "executor").
+
+`executor.html` (as a Document), `executor-worker.js` (as a Web Worker), and
+`executor-service-worker.js` (as a Service Worker) are examples of executors.
+Tests can send arbitrary javascript to these executors to evaluate in its
+execution context.
+
+This is universal and avoids introducing many specific `XXX-helper.html`
+resources.
+Moreover, tests are easier to read, because the whole logic of the test can be
+defined in a single file.
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/dispatcher.js b/testing/web-platform/tests/common/dispatcher/dispatcher.js
similarity index 90%
rename from testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/dispatcher.js
rename to testing/web-platform/tests/common/dispatcher/dispatcher.js
index 122983e85e1d6..8350933e80139 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/dispatcher.js
+++ b/testing/web-platform/tests/common/dispatcher/dispatcher.js
@@ -1,7 +1,6 @@
 // Define an universal message passing API. It works cross-origin and across
 // browsing context groups.
-const dispatcher_path =
-  "/html/cross-origin-embedder-policy/credentialless/resources/dispatcher.py";
+const dispatcher_path = "/common/dispatcher/dispatcher.py";
 const dispatcher_url = new URL(dispatcher_path, location.href).href;
 
 // Return a promise, limiting the number of concurrent accesses to a shared
@@ -78,6 +77,11 @@ const receive = async function(uuid) {
 // Returns an URL. When called, the server sends toward the `uuid` queue the
 // request headers. Useful for determining if something was requested with
 // Cookies.
-const showRequestHeaders= function(origin, uuid) {
+const showRequestHeaders = function(origin, uuid) {
   return origin + dispatcher_path + `?uuid=${uuid}&show-headers`;
 }
+
+// Same as above, except for the response is cacheable.
+const cacheableShowRequestHeaders = function(origin, uuid) {
+  return origin + dispatcher_path + `?uuid=${uuid}&cacheable&show-headers`;
+}
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/dispatcher.py b/testing/web-platform/tests/common/dispatcher/dispatcher.py
similarity index 84%
rename from testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/dispatcher.py
rename to testing/web-platform/tests/common/dispatcher/dispatcher.py
index 22d07229c77ba..9fe7a38ac87da 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/dispatcher.py
+++ b/testing/web-platform/tests/common/dispatcher/dispatcher.py
@@ -9,9 +9,13 @@ def main(request, response):
     response.headers.set(b"Access-Control-Allow-Credentials", b"true")
     response.headers.set(b'Access-Control-Allow-Methods', b'OPTIONS, GET, POST')
     response.headers.set(b'Access-Control-Allow-Headers', b'Content-Type')
-    response.headers.set(b'Cache-Control', b'no-cache, no-store, must-revalidate')
     response.headers.set(b"Access-Control-Allow-Origin", request.headers.get(b"origin") or '*')
 
+    if b"cacheable" in request.GET:
+        response.headers.set(b"Cache-Control", b"max-age=31536000")
+    else:
+        response.headers.set(b'Cache-Control', b'no-cache, no-store, must-revalidate')
+
     # CORS preflight
     if request.method == u'OPTIONS':
         return b''
@@ -22,7 +26,7 @@ def main(request, response):
     # The stash is accessed concurrently by many clients. A lock is used to
     # avoid unterleaved read/write from different clients.
     with stash.lock:
-        queue = stash.take(uuid, '/coep-credentialless') or [];
+        queue = stash.take(uuid, '/common/dispatcher') or [];
 
         # Push into the |uuid| queue, the requested headers.
         if b"show-headers" in request.GET:
@@ -45,5 +49,5 @@ def main(request, response):
             else:
                 ret = queue.pop(0)
 
-        stash.put(uuid, queue, '/coep-credentialless')
+        stash.put(uuid, queue, '/common/dispatcher')
     return ret;
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/sw_executor.js b/testing/web-platform/tests/common/dispatcher/executor-service-worker.js
similarity index 100%
rename from testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/sw_executor.js
rename to testing/web-platform/tests/common/dispatcher/executor-service-worker.js
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/executor.js b/testing/web-platform/tests/common/dispatcher/executor-worker.js
similarity index 100%
rename from testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/executor.js
rename to testing/web-platform/tests/common/dispatcher/executor-worker.js
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/resources/executor.html b/testing/web-platform/tests/common/dispatcher/executor.html
similarity index 69%
rename from testing/web-platform/tests/html/cross-origin-opener-policy/resources/executor.html
rename to testing/web-platform/tests/common/dispatcher/executor.html
index a4e92075c80b1..5fe6a95efaf97 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/resources/executor.html
+++ b/testing/web-platform/tests/common/dispatcher/executor.html
@@ -5,8 +5,10 @@
 const uuid = params.get('uuid');
 
 let executeOrders = async function() {
-  while(true)
-    eval(await receive(uuid));
+  while(true) {
+    let task = await receive(uuid);
+    eval(`(async () => {${task}})()`);
+  }
 };
 executeOrders();
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/anonymous-iframe-popup.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/anonymous-iframe-popup.tentative.https.html
index 0d1b6402f5da3..4326bb92d608b 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/anonymous-iframe-popup.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/anonymous-iframe-popup.tentative.https.html
@@ -4,8 +4,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="../credentialless/resources/common.js"></script>
-<script src="../credentialless/resources/dispatcher.js"></script>
 <body>
 <script>
 const {ORIGIN, REMOTE_ORIGIN} = get_host_info();
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/cookie.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/cookie.tentative.https.html
index 43282dd246e33..ad0df73e1292a 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/cookie.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/cookie.tentative.https.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="../credentialless/resources/common.js"></script>
-<script src="../credentialless/resources/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/local-storage.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/local-storage.tentative.https.html
index a49eac706bea9..7f673653d65a2 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/local-storage.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/anonymous-iframe/local-storage.tentative.https.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="../credentialless/resources/common.js"></script>
-<script src="../credentialless/resources/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/README.md b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/README.md
index 57de8e5353375..86654525dda61 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/README.md
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/README.md
@@ -1,15 +1,3 @@
-# Helper files:
-
-- `resources/dispatcher.js` provides `send()` and `receive()`. This is an
-  universal message passing API. It works cross-origin, and even access
-  different browser context groups. Messages are queued, this means one doesn't
-  need to wait for the receiver to listen, before sending the first message.
-
-- `resources/executor.html` is a document. Test can send arbitrary javascript to evaluate
-  in its execution context. This is universal and avoids introducing many
-  specific `XXX-helper.html` resources. Moreover, tests are easier to read,
-  because the whole logic of the test can be defined in a single file.
-
 # Related documents:
 - https://github.com/mikewest/credentiallessness/
 - https://github.com/w3ctag/design-reviews/issues/582
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cache-storage.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cache-storage.tentative.https.html
index 230f1048a7230..f4df73d6b8b42 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cache-storage.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cache-storage.tentative.https.html
@@ -7,8 +7,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
 // Fetch a resource and store it into CacheStorage from |storer| context. Then
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cache.tentative.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cache.tentative.html
index cc3ca16f6b3de..e28d6125107de 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cache.tentative.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cache.tentative.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
 // With COEP:credentialless, requesting a resource without credentials MUST NOT
@@ -24,8 +24,6 @@
 const cookie_value = "coep_cache_value";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
-const cacheable_response_path =
-  "/html/cross-origin-embedder-policy/credentialless/resources/cacheable-response.py";
 
 const GetCookie = (response) => {
  return parseCookies(JSON.parse(response))[cookie_key];
@@ -49,8 +47,7 @@
 
 // A request toward a "cross-origin" cacheable response.
 const request_token = token();
-const request_url = cross_origin + cacheable_response_path +
-  `?uuid=${request_token}`;
+const request_url = cacheableShowRequestHeaders(cross_origin, request_token);
 
 promise_setup(async test => {
   await setCookie(cross_origin, cookie_key, cookie_value + cookie_same_site_none);
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cross-origin-isolated.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cross-origin-isolated.html
index 86d30cdb458ff..f4286f14eb28e 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cross-origin-isolated.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/cross-origin-isolated.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
 const http  = get_host_info().HTTP_ORIGIN;
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/dedicated-worker.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/dedicated-worker.tentative.https.html
index 282a1ac91e7cc..a336c0c1ffa12 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/dedicated-worker.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/dedicated-worker.tentative.https.html
@@ -4,8 +4,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
 const same_origin = get_host_info().HTTPS_ORIGIN;
@@ -56,7 +56,7 @@
       const worker_error_1 = token();
       const worker_error_2  = token();
 
-      const w_worker_src_1 = same_origin + executor_js_path +
+      const w_worker_src_1 = same_origin + executor_worker_path +
         coep_for_worker + `&uuid=${worker_token_1}`;
       send(w_control_token, `
         new Worker("${w_worker_src_1}", {});
@@ -65,7 +65,7 @@
         }
       `);
 
-      const w_worker_src_2 = same_origin + executor_js_path +
+      const w_worker_src_2 = same_origin + executor_worker_path +
         coep_for_worker + `&uuid=${worker_token_2}`;
       send(w_credentialless_token, `
         const worker = new Worker("${w_worker_src_2}", {});
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/fetch.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/fetch.tentative.https.html
index fa2f2edd76b13..12531448afcc4 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/fetch.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/fetch.tentative.https.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
 promise_test(async test => {
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-credentialless.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-credentialless.tentative.https.html
index eee911cea7d08..c1a47c5fcc132 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-credentialless.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-credentialless.tentative.https.html
@@ -5,8 +5,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script src="./resources/iframeTest.js"></script>
 <script src="/common/subset-tests.js"></script>
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-none.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-none.tentative.https.html
index 3596a5473b8df..897396cde389d 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-none.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-none.tentative.https.html
@@ -4,8 +4,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script src="./resources/iframeTest.js"></script>
 <script src="/common/subset-tests.js"></script>
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-require-corp.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-require-corp.tentative.https.html
index 41e0c65643e24..4e9f939bbf2f9 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-require-corp.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe-coep-require-corp.tentative.https.html
@@ -5,8 +5,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script src="./resources/iframeTest.js"></script>
 <script src="/common/subset-tests.js"></script>
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe.tentative.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe.tentative.html
index 81bc0fc13b873..832a7044791e3 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe.tentative.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/iframe.tentative.html
@@ -3,8 +3,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 
 <script>
 const same_origin = get_host_info().HTTPS_ORIGIN;
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/image.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/image.tentative.https.html
index 11449ee49b310..18373db0a4812 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/image.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/image.tentative.https.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/link.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/link.tentative.https.html
index fb17bf24f560b..a12f7041a052a 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/link.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/link.tentative.https.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/redirect.tentative.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/redirect.tentative.html
index 07b7a0f9bd571..219de4a966869 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/redirect.tentative.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/redirect.tentative.html
@@ -3,8 +3,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 
 <script>
 const same_origin = get_host_info().HTTPS_ORIGIN;
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/cacheable-response.py b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/cacheable-response.py
deleted file mode 100644
index 103b7f7255d8f..0000000000000
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/cacheable-response.py
+++ /dev/null
@@ -1,24 +0,0 @@
-import json
-from wptserve.utils import isomorphic_decode
-
-# A server providing a cacheable response and storing the request's headers
-# toward the `uuid` attribute stash.
-def main(request, response):
-    # The response served is cacheable by the navigator:
-    response.headers.set(b"Cache-Control", b"max-age=31536000");
-
-    uuid = request.GET[b'uuid'];
-    headers = {};
-    for key, value in request.headers.items():
-        headers[isomorphic_decode(key)] = isomorphic_decode(request.headers[key])
-    headers = json.dumps(headers);
-
-    # The stash is accessed concurrently by many clients. A lock is used to
-    # avoid unterleaved read/write from different clients.
-    stash = request.server.stash;
-    with stash.lock:
-        queue = stash.take(uuid, '/coep-credentialless') or [];
-        queue.append(headers);
-        stash.put(uuid, queue, '/coep-credentialless');
-    return b"done";
-
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/common.js b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/common.js
index eebba79ffb612..85e539a422da8 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/common.js
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/common.js
@@ -1,7 +1,6 @@
-const directory = '/html/cross-origin-embedder-policy/credentialless';
-const executor_path = directory + '/resources/executor.html?pipe=';
-const executor_js_path = directory + '/resources/executor.js?pipe=';
-const sw_executor_js_path = directory + '/resources/sw_executor.js?pipe=';
+const executor_path = '/common/dispatcher/executor.html?pipe=';
+const executor_worker_path = '/common/dispatcher/executor-worker.js?pipe=';
+const executor_service_worker_path = '/common/dispatcher/executor-service-worker.js?pipe=';
 
 // COEP
 const coep_none =
@@ -108,21 +107,21 @@ const environments = {
 
   dedicated_worker: headers => {
     const tok = token();
-    const url = window.origin + executor_js_path + headers + `&uuid=${tok}`;
+    const url = window.origin + executor_worker_path + headers + `&uuid=${tok}`;
     const context = new Worker(url);
     return [tok, new Promise(resolve => context.onerror = resolve)];
   },
 
   shared_worker: headers => {
     const tok = token();
-    const url = window.origin + executor_js_path + headers + `&uuid=${tok}`;
+    const url = window.origin + executor_worker_path + headers + `&uuid=${tok}`;
     const context = new SharedWorker(url);
     return [tok, new Promise(resolve => context.onerror = resolve)];
   },
 
   service_worker: headers => {
     const tok = token();
-    const url = window.origin + executor_js_path + headers + `&uuid=${tok}`;
+    const url = window.origin + executor_worker_path + headers + `&uuid=${tok}`;
     const scope = url; // Generate a one-time scope for service worker.
     const error = new Promise(resolve => {
       navigator.serviceWorker.register(url, {scope: scope})
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/executor.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/executor.html
deleted file mode 100644
index 7a390a3d7e991..0000000000000
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/resources/executor.html
+++ /dev/null
@@ -1,15 +0,0 @@
-<script src="./dispatcher.js"></script>
-<script>
-
-  const params = new URLSearchParams(window.location.search);
-  const uuid = params.get('uuid');
-
-  let executeOrders = async function() {
-    while(true) {
-      let task = await receive(uuid);
-      eval(`(async () => {${task}})()`);
-    }
-  };
-  executeOrders();
-
-</script>
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/script.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/script.tentative.https.html
index 45464dc4d38de..6a3f6559cb360 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/script.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/script.tentative.https.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker-coep-credentialless-proxy.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker-coep-credentialless-proxy.tentative.https.html
index fe12ec8d263b9..05e044f9f4a06 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker-coep-credentialless-proxy.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker-coep-credentialless-proxy.tentative.https.html
@@ -2,12 +2,11 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script src="/service-workers/service-worker/resources/test-helpers.sub.js"></script>
 <script>
 
-const resource_path = directory + "/resources/";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
 
@@ -18,9 +17,11 @@
   // Register a COEP:credentialless ServiceWorker.
   const sw_token = token();
   const sw_url =
-    sw_executor_js_path + coep_credentialless + `&uuid=${sw_token}`;
+    executor_service_worker_path + coep_credentialless + `&uuid=${sw_token}`;
+  // Executors should be controlled by the service worker.
+  const scope = executor_path;
   const sw_registration =
-    await service_worker_unregister_and_register(test, sw_url, resource_path);
+    await service_worker_unregister_and_register(test, sw_url, scope);
   test.add_cleanup(() => sw_registration.unregister());
   await wait_for_state(test, sw_registration.installing, 'activated');
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker-coep-none-proxy.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker-coep-none-proxy.tentative.https.html
index 599623bc54ddb..2ab9f92bac0bd 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker-coep-none-proxy.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker-coep-none-proxy.tentative.https.html
@@ -2,12 +2,11 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script src="/service-workers/service-worker/resources/test-helpers.sub.js"></script>
 <script>
 
-const resource_path = directory + "/resources/";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
 
@@ -17,9 +16,11 @@
 
   // Register a COEP:none ServiceWorker.
   const sw_token = token();
-  const sw_url = sw_executor_js_path + coep_none + `&uuid=${sw_token}`;
+  const sw_url = executor_service_worker_path + coep_none + `&uuid=${sw_token}`;
+  // Executors should be controlled by the service worker.
+  const scope = executor_path;
   const sw_registration =
-    await service_worker_unregister_and_register(test, sw_url, resource_path);
+    await service_worker_unregister_and_register(test, sw_url, scope);
   test.add_cleanup(() => sw_registration.unregister());
   await wait_for_state(test, sw_registration.installing, 'activated');
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker.tentative.https.html
index 3e730cac9d9e8..ec7c7d69379a7 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/service-worker.tentative.https.html
@@ -4,9 +4,9 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/service-workers/service-worker/resources/test-helpers.sub.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
 const same_origin = get_host_info().HTTPS_ORIGIN;
@@ -49,13 +49,13 @@
       const control_worker_token = token();
       const credentialless_worker_token = token();
 
-      const w_control_worker_src = same_origin + executor_js_path +
+      const w_control_worker_src = same_origin + executor_worker_path +
         coep_for_worker + `&uuid=${control_worker_token}`;
       const w_control_worker_reg =
         await service_worker_unregister_and_register(
           test, w_control_worker_src, w_control_url);
 
-      const w_credentialless_worker_src = same_origin + executor_js_path +
+      const w_credentialless_worker_src = same_origin + executor_worker_path +
         coep_for_worker + `&uuid=${credentialless_worker_token}`;
       const w_credentialless_worker_reg =
         await service_worker_unregister_and_register(
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/shared-worker.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/shared-worker.tentative.https.html
index da400c8e98ab7..ba8965d66b03d 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/shared-worker.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/shared-worker.tentative.https.html
@@ -4,8 +4,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
 const same_origin = get_host_info().HTTPS_ORIGIN;
@@ -55,7 +55,7 @@
       const worker_error_1 = token();
       const worker_error_2 = token();
 
-      const w_worker_src_1 = same_origin + executor_js_path +
+      const w_worker_src_1 = same_origin + executor_worker_path +
         coep_for_worker + `&uuid=${worker_token_1}`;
       send(w_control_token, `
         let worker = new SharedWorker("${w_worker_src_1}", {});
@@ -64,7 +64,7 @@
         }
       `);
 
-      const w_worker_src_2 = same_origin + executor_js_path +
+      const w_worker_src_2 = same_origin + executor_worker_path +
         coep_for_worker + `&uuid=${worker_token_2}`;
       send(w_credentialless_token, `
         let worker = new SharedWorker("${w_worker_src_2}", {});
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/video.tentative.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/video.tentative.https.html
index a64fbbc323420..97b8509f3a5c2 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/video.tentative.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/credentialless/video.tentative.https.html
@@ -2,8 +2,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/iframe-history-none-require-corp.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/iframe-history-none-require-corp.https.html
index 384c6840d11cc..0e7ef8108b1cc 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/iframe-history-none-require-corp.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/iframe-history-none-require-corp.https.html
@@ -8,7 +8,7 @@
 promise_test(async test => {
   // TODO(arthursonzogni): Consider switching toward another message passing
   // API like:
-  // /html/cross-origin-embedder-policy/credentialless/resources/dispatcher.js
+  // /common/dispatcher/dispatcher.js
   const bc = new BroadcastChannel(token());
   const futureMessage = () => {
     return new Promise(resolve => {
diff --git a/testing/web-platform/tests/html/cross-origin-embedder-policy/none.https.html b/testing/web-platform/tests/html/cross-origin-embedder-policy/none.https.html
index 004924ade41b0..cf9b34b4ca967 100644
--- a/testing/web-platform/tests/html/cross-origin-embedder-policy/none.https.html
+++ b/testing/web-platform/tests/html/cross-origin-embedder-policy/none.https.html
@@ -45,7 +45,7 @@
   let pageLoaded = false;
   // TODO(arthursonzogni): Consider switching toward another message passing
   // API like:
-  // /html/cross-origin-embedder-policy/credentialless/resources/dispatcher.js
+  // /common/dispatcher/dispatcher.js
   const bc = new BroadcastChannel(token());
   let finished = false;
   let doneCheck = _ => {
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/coop-navigate-same-origin-csp-sandbox.html b/testing/web-platform/tests/html/cross-origin-opener-policy/coop-navigate-same-origin-csp-sandbox.html
index e6ed947172276..83113de376acc 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/coop-navigate-same-origin-csp-sandbox.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/coop-navigate-same-origin-csp-sandbox.html
@@ -2,12 +2,11 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="./resources/common.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
-const directory = '/html/cross-origin-opener-policy/';
-const executor_path = directory + '/resources/executor.html?pipe=';
+const executor_path = '/common/dispatcher/executor.html?pipe=';
 
 const https_origin = get_host_info().HTTPS_ORIGIN;
 const coop_same_origin =
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/coop-same-origin-allow-popups-document-write.html b/testing/web-platform/tests/html/cross-origin-opener-policy/coop-same-origin-allow-popups-document-write.html
index 45ba24bd71d71..82dd4541b6e2f 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/coop-same-origin-allow-popups-document-write.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/coop-same-origin-allow-popups-document-write.html
@@ -3,7 +3,7 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
-<script src="./resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script>
 
 /*
@@ -13,8 +13,7 @@
   meta refresh. The openee/opener relationship must hold.
 */
 
-const directory = '/html/cross-origin-opener-policy';
-const executor_path = directory + '/resources/executor.html?pipe=';
+const executor_path = '/common/dispatcher/executor.html?pipe=';
 const coep_soap =
   "|header(Cross-Origin-Opener-Policy,same-origin-allow-popups)";
 const same_origin = get_host_info().HTTPS_ORIGIN;
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/navigate-to-aboutblank.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/navigate-to-aboutblank.https.html
index 4aa39e392787c..b2145cfa56730 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/navigate-to-aboutblank.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/navigate-to-aboutblank.https.html
@@ -6,7 +6,7 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 
 <p>Non-initial empty documents (about:blank) should inherit their
   cross-origin-opener-policy from the navigation's initiator top level document,
@@ -24,8 +24,7 @@
 </ol>
 
 <script>
-const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
+const executor_path = "/common/dispatcher/executor.html?pipe=";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
 const coop_same_origin_header =
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/navigate-top-to-aboutblank.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/navigate-top-to-aboutblank.https.html
index c4bbe15000c92..fe605baf45a53 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/navigate-top-to-aboutblank.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/navigate-top-to-aboutblank.https.html
@@ -6,8 +6,8 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 
 
 <p>Non-initial empty documents (about:blank) should inherit their
@@ -28,8 +28,7 @@
 </ol>
 
 <script>
-const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
+const executor_path = "/common/dispatcher/executor.html?pipe=";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
 const coop_same_origin_header =
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/popup-coop-by-sw.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/popup-coop-by-sw.https.html
index 6d6ace1fd6299..69c2db1ad939b 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/popup-coop-by-sw.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/popup-coop-by-sw.https.html
@@ -6,13 +6,12 @@
 <script src="/common/subset-tests.js"></script>
 <script src="/service-workers/service-worker/resources/test-helpers.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/common/get-host-info.sub.js"></script>
-<script src="./resources/dispatcher.js"></script>
 <script>
 
-const resources = "/html/cross-origin-opener-policy/resources";
-const executor_path = resources + "/executor.html?pipe=";
-const sw_executor_path  = resources + "/sw_executor.js?pipe=";
+const executor_path = '/common/dispatcher/executor.html?pipe=';
+const executor_service_worker_path = '/common/dispatcher/executor-service-worker.js?pipe=';
 
 const coop_header = `|header(Cross-Origin-Opener-Policy,same-origin)`;
 const coep_header = `|header(Cross-Origin-Embedder-Policy,require-corp)`;
@@ -60,11 +59,11 @@
     test.add_cleanup(() => opener_window.close());
 
     // 2. Define the openee's URL as being served by the service worker.
-    const openee_url = https_origin + resources + "/proxied?" + token();
+    const openee_url = https_origin + "/common/dispatcher/proxied?" + token();
 
     // 3. Register, install and activate a ServiceWorker serving the openee_url.
     const sw_token = token();
-    const sw_url = https_origin + sw_executor_path + sw_headers +
+    const sw_url = https_origin + executor_service_worker_path + sw_headers +
       `&uuid=${sw_token}`;
     const sw_scope = openee_url; // One-time scope, because of the token.
 
@@ -79,7 +78,7 @@
           return;
 
         const response = new Response(\`
-          <script src="./dispatcher.js"></scr\`+\`ipt>
+          <script src="/common/dispatcher/dispatcher.js"></scr\`+\`ipt>
           <script>
             send("${driver_token}", opener ? "opener is set"
                                            : "opener is null");
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/popup-redirect-same-origin-allow-popups.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/popup-redirect-same-origin-allow-popups.https.html
index 7145d4c1cdd4e..73119a76f8729 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/popup-redirect-same-origin-allow-popups.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/popup-redirect-same-origin-allow-popups.https.html
@@ -8,12 +8,12 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 
 <div id=log></div>
 <script>
 
-const executor_path = "/html/cross-origin-opener-policy/resources/executor.html?pipe=";
+const executor_path = "/common/dispatcher/executor.html?pipe=";
 const same_origin = {
   host: get_host_info().HTTPS_ORIGIN,
   name: "Same origin"
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-openee_coop-ro.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-openee_coop-ro.https.html
index 0a98e3bd3b7e6..a7e83cc0d921f 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-openee_coop-ro.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-openee_coop-ro.https.html
@@ -7,16 +7,15 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const redirect_path = directory + "/resources/redirect.py?";
 const same_origin = get_host_info().HTTPS_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let runTest = (openee_redirect, name) => promise_test(async t => {
   // The test window.
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-openee_coop-ro_cross-origin.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-openee_coop-ro_cross-origin.https.html
index 58bfb6c5da94a..fe72a2299fdd9 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-openee_coop-ro_cross-origin.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-openee_coop-ro_cross-origin.https.html
@@ -7,17 +7,16 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const redirect_path = directory + "/resources/redirect.py?";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let runTest = (openee_redirect, name) => promise_test(async t => {
   // The test window.
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-opener_coop-ro.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-opener_coop-ro.https.html
index ea58b66db239f..005339a06ec59 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-opener_coop-ro.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-opener_coop-ro.https.html
@@ -7,16 +7,15 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const redirect_path = directory + "/resources/redirect.py?";
 const same_origin = get_host_info().HTTPS_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let runTest = (openee_redirect, name) => promise_test(async t => {
   const report_token = token();
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-opener_coop-ro_cross-origin.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-opener_coop-ro_cross-origin.https.html
index e19cc944a0e70..eedfaa557f81c 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-opener_coop-ro_cross-origin.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-opener_coop-ro_cross-origin.https.html
@@ -7,17 +7,16 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const redirect_path = directory + "/resources/redirect.py?";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let runTest = (openee_redirect, name) => promise_test(async t => {
   const report_token = token();
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-other_coop-ro.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-other_coop-ro.https.html
index bbb1f07ff3250..90df0e4e9950e 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-other_coop-ro.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-other_coop-ro.https.html
@@ -9,15 +9,14 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const same_origin = get_host_info().HTTPS_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let escapeComma = url => url.replace(/,/g, '\\,');
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-other_coop-ro_cross-origin.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-other_coop-ro_cross-origin.https.html
index c1058242ab28a..f0d60c25310bb 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-other_coop-ro_cross-origin.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-from-coop-page-to-other_coop-ro_cross-origin.https.html
@@ -9,16 +9,15 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const same_origin= get_host_info().HTTPS_ORIGIN;
 const cross_origin= get_host_info().HTTPS_REMOTE_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let escapeComma = url => url.replace(/,/g, '\\,');
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-openee_coop-ro.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-openee_coop-ro.https.html
index 923676477baee..9f0a8821a457a 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-openee_coop-ro.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-openee_coop-ro.https.html
@@ -7,16 +7,15 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const redirect_path = directory + "/resources/redirect.py?";
 const same_origin = get_host_info().HTTPS_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let runTest = (openee_redirect, name) => promise_test(async t => {
   // The test window.
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-openee_coop-ro_cross-origin.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-openee_coop-ro_cross-origin.https.html
index f19ec50536e53..d9577836d9cb8 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-openee_coop-ro_cross-origin.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-openee_coop-ro_cross-origin.https.html
@@ -7,17 +7,16 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const redirect_path = directory + "/resources/redirect.py?";
 const same_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
 const cross_origin= get_host_info().HTTPS_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let runTest = (openee_redirect, name) => promise_test(async t => {
   // The test window.
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-opener_coop-ro.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-opener_coop-ro.https.html
index 3b459cf5124fa..8a643d762c854 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-opener_coop-ro.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-opener_coop-ro.https.html
@@ -7,15 +7,14 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const redirect_path = directory + "/resources/redirect.py?";
 const same_origin = get_host_info().HTTPS_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let runTest = (openee_redirect, name) => promise_test(async t => {
   const report_token = token();
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-opener_coop-ro_cross-origin.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-opener_coop-ro_cross-origin.https.html
index 3b123eb6562c3..7e1ae870a72b6 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-opener_coop-ro_cross-origin.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-opener_coop-ro_cross-origin.https.html
@@ -7,16 +7,15 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const redirect_path = directory + "/resources/redirect.py?";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let runTest = (openee_redirect, name) => promise_test(async t => {
   const report_token = token();
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-other_coop-ro.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-other_coop-ro.https.html
index af1514f0d301b..b73bab8610f3f 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-other_coop-ro.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-other_coop-ro.https.html
@@ -9,15 +9,14 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const same_origin = get_host_info().HTTPS_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 promise_test(async t => {
   // The test window.
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-other_coop-ro_cross-origin.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-other_coop-ro_cross-origin.https.html
index 523d03904b303..c86daa3dcad5b 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-other_coop-ro_cross-origin.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/access-to-coop-page-from-other_coop-ro_cross-origin.https.html
@@ -9,16 +9,15 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 promise_test(async t => {
   // The test window.
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-blur.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-blur.https.html
index 435ae592046ad..849bf6579aa15 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-blur.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-blur.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-close.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-close.https.html
index 308236eb69702..7696600488906 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-close.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-close.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-closed.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-closed.https.html
index afb9c5ed4dc6d..c678d18a80da4 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-closed.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-closed.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-focus.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-focus.https.html
index 231a2e8fe8065..363c0d294f817 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-focus.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-focus.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-frames.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-frames.https.html
index a5c0f2a7d0a92..fc1925045f65f 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-frames.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-frames.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-indexed-getter.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-indexed-getter.https.html
index 07d6cd41e0fa3..b6c5f5acb1f1a 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-indexed-getter.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-indexed-getter.https.html
@@ -4,11 +4,11 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
+const executor_path = "/common/dispatcher/executor.html?pipe=";
 const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let origin = [
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-length.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-length.https.html
index 6a3b76b2143a5..a9f3614cb5113 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-length.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-length.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-location-get.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-location-get.https.html
index 78ae18f6eb07a..442817748d871 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-location-get.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-location-get.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-location-set.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-location-set.https.html
index 96c57296a713a..e42f08482197c 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-location-set.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-location-set.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-named-getter.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-named-getter.https.html
index 83eb611868e97..27be9a48d1830 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-named-getter.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-named-getter.https.html
@@ -4,11 +4,10 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script>
 
-const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
+const executor_path = "/common/dispatcher/executor.html?pipe=";
 let crossOrigin = ["cross-origin" , get_host_info().HTTPS_REMOTE_ORIGIN ];
 let sameOrigin =  ["same-site"    , get_host_info().HTTPS_ORIGIN        ];
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-opener-get.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-opener-get.https.html
index f52345fbc5b89..b99dfdc562424 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-opener-get.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-opener-get.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-opener-set.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-opener-set.https.html
index af1065f7754ba..478fc5c82fe25 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-opener-set.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-opener-set.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-postmessage-1.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-postmessage-1.https.html
index 47447cc06816f..a9168fdaa5b56 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-postmessage-1.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-postmessage-1.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-postmessage-2.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-postmessage-2.https.html
index 1779b3d9b7909..4341f245d5c6d 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-postmessage-2.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-postmessage-2.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-self.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-self.https.html
index a10448d4a1001..7a7d5a3fecaed 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-self.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-self.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-top.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-top.https.html
index 3470c4f17c96a..1b75ecc1058df 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-top.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-top.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-window.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-window.https.html
index 66000061f694e..07278b4a11d44 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-window.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/property-window.https.html
@@ -3,7 +3,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/test-access-property.js"></script>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/report-to-both_coop-ro.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/report-to-both_coop-ro.https.html
index 0560431f9932f..46cdc6eb271ff 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/report-to-both_coop-ro.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/report-to-both_coop-ro.https.html
@@ -7,16 +7,15 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const origin_opener = get_host_info().HTTPS_ORIGIN;
 const origin_openee = get_host_info().HTTPS_REMOTE_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 let escapeComma = url => url.replace(/,/g, '\\,');
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/reporting-observer.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/reporting-observer.html
index efbe9c7ce6a92..375c627d27290 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/reporting-observer.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/access-reporting/reporting-observer.html
@@ -9,16 +9,15 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/try-access.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_site = get_host_info().HTTPS_NOTSAMESITE_ORIGIN;
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 const corp_header = '|header(Cross-Origin-Resource-Policy,cross-origin)';
 
 promise_test(async t => {
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-four-reports.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-four-reports.https.html
index 7b032b9dc15f5..95e87e61bb75a 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-four-reports.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-four-reports.https.html
@@ -5,8 +5,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-from-unsafe-none.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-from-unsafe-none.https.html
index 6624bf0de271b..cca2e7e1ae88a 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-from-unsafe-none.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-from-unsafe-none.https.html
@@ -5,8 +5,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-report-to.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-report-to.https.html
index 3f6c064fb205f..d61b987887ef7 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-report-to.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-report-to.https.html
@@ -5,8 +5,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-with-coep-report-only.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-with-coep-report-only.https.html
index af21bd8fcd2f5..148c700ee5018 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-with-coep-report-only.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-with-coep-report-only.https.html
@@ -5,8 +5,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-with-coep.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-with-coep.https.html
index af21bd8fcd2f5..148c700ee5018 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-with-coep.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin-with-coep.https.html
@@ -5,8 +5,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin.https.html
index ffa6bb8be73f9..8a63682c69ce8 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/report-only-same-origin.https.html
@@ -5,8 +5,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-opener.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-opener.https.html
index a546c26e856ef..487a4665d79c1 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-opener.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-opener.https.html
@@ -6,11 +6,11 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const same_origin = get_host_info().HTTPS_ORIGIN;
 
 let escapeComma = url => url.replace(/,/g, '\\,');
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-popup.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-popup.https.html
index 0fda47e3230b6..70e5eae996736 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-popup.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-coop-navigated-popup.https.html
@@ -2,7 +2,7 @@
 <script src=/resources/testharness.js></script>
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/utils.js"></script> <!-- Use token() to allow running tests in parallel -->
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-allow-popups-report-to.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-allow-popups-report-to.https.html
index 6f464c1a30100..760db13dcec2a 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-allow-popups-report-to.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-allow-popups-report-to.https.html
@@ -4,8 +4,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-coep-report-to.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-coep-report-to.https.html
index 0b3c6f8fec0e0..06170f68e3f2f 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-coep-report-to.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-coep-report-to.https.html
@@ -4,8 +4,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>>
 <script>
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-report-to.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-report-to.https.html
index d478cd0bbc3e4..cee3aae692f8c 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-report-to.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin-report-to.https.html
@@ -4,8 +4,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin.https.html
index b9c6844ce84ba..3a8f343f37148 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-same-origin.https.html
@@ -4,8 +4,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-unsafe-none-report-to.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-unsafe-none-report-to.https.html
index f2fef9f6c9d0c..4e8ce4fe6bfcc 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-unsafe-none-report-to.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-popup-unsafe-none-report-to.https.html
@@ -4,8 +4,8 @@
 <script src=/resources/testharnessreport.js></script>
 <script src="/common/get-host-info.sub.js"></script>
 <script src="/common/utils.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/resources/common.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
 <script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 
 <script>
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-redirect-with-same-origin-allow-popups.https.html b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-redirect-with-same-origin-allow-popups.https.html
index b40b32ec74c36..d337541dfff01 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-redirect-with-same-origin-allow-popups.https.html
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/navigation-reporting/reporting-redirect-with-same-origin-allow-popups.https.html
@@ -6,11 +6,11 @@
 <script src=/resources/testharnessreport.js></script>
 <script src=/common/get-host-info.sub.js></script>
 <script src="/common/utils.js"></script>
-<script src="/html/cross-origin-opener-policy/resources/dispatcher.js"></script>
+<script src="/common/dispatcher/dispatcher.js"></script>
+<script src="/html/cross-origin-opener-policy/reporting/resources/reporting-common.js"></script>
 <script>
 
 const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
 const same_origin = {
   host: get_host_info().HTTPS_ORIGIN,
   name: "Same origin"
@@ -19,7 +19,6 @@
   host: get_host_info().HTTPS_REMOTE_ORIGIN,
   name: "Cross origin"
 };
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 // Tests the redirect interaction with COOP same-origin-allow-popups and
 // reporting:
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/resources/reporting-common.js b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/resources/reporting-common.js
index ddccb14def783..e44a70426d727 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/resources/reporting-common.js
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/resources/reporting-common.js
@@ -1,6 +1,4 @@
-
-const directory = "/html/cross-origin-opener-policy/resources";
-const executor_path = directory + "/executor.html?pipe=";
+const executor_path = "/common/dispatcher/executor.html?pipe=";
 const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
 
 // Allows RegExps to be pretty printed when printing unmatched expected reports.
@@ -243,3 +241,43 @@ function verifyRemainingReports() {
     }));
   }, "verify remaining reports");
 }
+
+const receiveReport = async function(uuid, type) {
+  while(true) {
+    let reports = await receive(uuid);
+    if (reports == "timeout")
+      return "timeout";
+    reports = JSON.parse(reports);
+
+    for(report of reports) {
+      if (report?.body?.type == type)
+        return report;
+    }
+  }
+}
+
+// Build a set of headers to tests the reporting API. This defines a set of
+// matching 'Report-To', 'Cross-Origin-Opener-Policy' and
+// 'Cross-Origin-Opener-Policy-Report-Only' headers.
+const reportToHeaders = function(uuid) {
+  const report_endpoint_url = dispatcher_path + `?uuid=${uuid}`;
+  let reportToJSON = {
+    'group': `${uuid}`,
+    'max_age': 3600,
+    'endpoints': [
+      {'url': report_endpoint_url.toString()},
+    ]
+  };
+  reportToJSON = JSON.stringify(reportToJSON)
+                     .replace(/,/g, '\\,')
+                     .replace(/\(/g, '\\\(')
+                     .replace(/\)/g, '\\\)=');
+
+  return {
+    header: `|header(report-to,${reportToJSON})`,
+    coopSameOriginHeader: `|header(Cross-Origin-Opener-Policy,same-origin%3Breport-to="${uuid}")`,
+    coopSameOriginAllowPopupsHeader: `|header(Cross-Origin-Opener-Policy,same-origin-allow-popups%3Breport-to="${uuid}")`,
+    coopReportOnlySameOriginHeader: `|header(Cross-Origin-Opener-Policy-Report-Only,same-origin%3Breport-to="${uuid}")`,
+    coopReportOnlySameOriginAllowPopupsHeader: `|header(Cross-Origin-Opener-Policy-Report-Only,same-origin-allow-popups%3Breport-to="${uuid}")`,
+  };
+};
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/resources/test-access-property.js b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/resources/test-access-property.js
index 4b5466a72f043..c8c0ea2f537cd 100644
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/resources/test-access-property.js
+++ b/testing/web-platform/tests/html/cross-origin-opener-policy/reporting/resources/test-access-property.js
@@ -1,7 +1,3 @@
-const directory = "/html/cross-origin-opener-policy";
-const executor_path = directory + "/resources/executor.html?pipe=";
-const coep_header = '|header(Cross-Origin-Embedder-Policy,require-corp)';
-
 const same_origin = get_host_info().HTTPS_ORIGIN;
 const cross_origin = get_host_info().HTTPS_REMOTE_ORIGIN;
 
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/resources/dispatcher.js b/testing/web-platform/tests/html/cross-origin-opener-policy/resources/dispatcher.js
deleted file mode 100644
index 81dbbccb9514a..0000000000000
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/resources/dispatcher.js
+++ /dev/null
@@ -1,94 +0,0 @@
-// Define an universal message passing API.
-//
-// In particular, this works:
-// - cross-origin and
-// - cross-browsing-context-group.
-//
-// It can also be used to receive reports.
-
-const dispatcher_path =
-    '/html/cross-origin-opener-policy/resources/dispatcher.py';
-const dispatcher_url = new URL(dispatcher_path, location.href).href;
-
-// Return a promise, limiting the number of concurrent accesses to a shared
-// resources to |max_concurrent_access|.
-const concurrencyLimiter = (max_concurrency) => {
-  let pending = 0;
-  let waiting = [];
-  return async (task) => {
-    pending++;
-    if (pending > max_concurrency)
-      await new Promise(resolve => waiting.push(resolve));
-    await task();
-    pending--;
-    waiting.shift()?.();
-  };
-}
-
-// The official web-platform-test runner sometimes drop POST requests when
-// too many are requested in parallel. Limiting this document to send only one
-// at a time fixes the issue.
-const sendLimiter = concurrencyLimiter(1);
-
-const send = async function(uuid, message) {
-  await sendLimiter(async () => {
-    await fetch(dispatcher_url + `?uuid=${uuid}`, {
-      method: 'POST',
-      body: message
-    });
-  });
-}
-
-const receive = async function(uuid, maybe_timeout) {
-  const timeout = maybe_timeout || Infinity;
-  let start = performance.now();
-  while(performance.now() - start < timeout) {
-    let response = await fetch(dispatcher_url + `?uuid=${uuid}`);
-    let data = await response.text();
-    if (data != 'not ready')
-      return data;
-    // Save resources & spread the load:
-    await new Promise(r => setTimeout(r, 100*Math.random()));
-  }
-  return "timeout";
-}
-
-const receiveReport = async function(uuid, type) {
-  while(true) {
-    let reports = await receive(uuid);
-    if (reports == "timeout")
-      return "timeout";
-    reports = JSON.parse(reports);
-
-    for(report of reports) {
-      if (report?.body?.type == type)
-        return report;
-    }
-  }
-}
-
-// Build a set of headers to tests the reporting API. This defines a set of
-// matching 'Report-To', 'Cross-Origin-Opener-Policy' and
-// 'Cross-Origin-Opener-Policy-Report-Only' headers.
-const reportToHeaders = function(uuid) {
-  const report_endpoint_url = dispatcher_path + `?uuid=${uuid}`;
-  let reportToJSON = {
-    'group': `${uuid}`,
-    'max_age': 3600,
-    'endpoints': [
-      {'url': report_endpoint_url.toString()},
-    ]
-  };
-  reportToJSON = JSON.stringify(reportToJSON)
-                     .replace(/,/g, '\\,')
-                     .replace(/\(/g, '\\\(')
-                     .replace(/\)/g, '\\\)=');
-
-  return {
-    header: `|header(report-to,${reportToJSON})`,
-    coopSameOriginHeader: `|header(Cross-Origin-Opener-Policy,same-origin%3Breport-to="${uuid}")`,
-    coopSameOriginAllowPopupsHeader: `|header(Cross-Origin-Opener-Policy,same-origin-allow-popups%3Breport-to="${uuid}")`,
-    coopReportOnlySameOriginHeader: `|header(Cross-Origin-Opener-Policy-Report-Only,same-origin%3Breport-to="${uuid}")`,
-    coopReportOnlySameOriginAllowPopupsHeader: `|header(Cross-Origin-Opener-Policy-Report-Only,same-origin-allow-popups%3Breport-to="${uuid}")`,
-  };
-};
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/resources/dispatcher.py b/testing/web-platform/tests/html/cross-origin-opener-policy/resources/dispatcher.py
deleted file mode 100644
index e77583e479f95..0000000000000
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/resources/dispatcher.py
+++ /dev/null
@@ -1,27 +0,0 @@
-# A server used to store and retrieve arbitrary data.
-# This is used by: ./dispatcher.js
-def main(request, response):
-    response.headers.set(b'Access-Control-Allow-Origin', b'*')
-    response.headers.set(b'Access-Control-Allow-Methods', b'OPTIONS, GET, POST')
-    response.headers.set(b'Access-Control-Allow-Headers', b'Content-Type')
-    response.headers.set(b'Cache-Control', b'no-cache, no-store, must-revalidate')
-    if request.method == u'OPTIONS': # CORS preflight
-        return b''
-
-    uuid = request.GET[b'uuid']
-    stash = request.server.stash;
-    with stash.lock:
-        queue = stash.take(uuid)
-        if queue is None:
-            queue = []
-
-        if request.method == u'POST':
-            queue.append(request.body)
-            ret = b'done'
-        else:
-            if len(queue) == 0:
-                ret = b'not ready'
-            else:
-                ret = queue.pop(0)
-        stash.put(uuid, queue)
-    return ret;
diff --git a/testing/web-platform/tests/html/cross-origin-opener-policy/resources/sw_executor.js b/testing/web-platform/tests/html/cross-origin-opener-policy/resources/sw_executor.js
deleted file mode 100644
index 0b47d66b65f06..0000000000000
--- a/testing/web-platform/tests/html/cross-origin-opener-policy/resources/sw_executor.js
+++ /dev/null
@@ -1,24 +0,0 @@
-importScripts('./dispatcher.js');
-
-const params = new URLSearchParams(location.search);
-const uuid = params.get('uuid');
-
-// The fetch handler must be registered before parsing the main script response.
-// So do it here, for future use.
-fetchHandler = () => {}
-addEventListener('fetch', e => {
-  fetchHandler(e);
-});
-
-// Force ServiceWorker to immediately activate itself.
-addEventListener('install', event => {
-  skipWaiting();
-});
-
-let executeOrders = async function() {
-  while(true) {
-    let task = await receive(uuid);
-    eval(`(async () => {${task}})()`);
-  }
-};
-executeOrders();
diff --git a/testing/web-platform/tests/lint.ignore b/testing/web-platform/tests/lint.ignore
index cd5ca8ad2361f..5d43121c5aec1 100644
--- a/testing/web-platform/tests/lint.ignore
+++ b/testing/web-platform/tests/lint.ignore
@@ -161,7 +161,6 @@ SET TIMEOUT: html/browsers/history/the-location-interface/*
 SET TIMEOUT: html/browsers/history/the-session-history-of-browsing-contexts/*
 SET TIMEOUT: html/browsers/offline/*
 SET TIMEOUT: html/browsers/the-window-object/*
-SET TIMEOUT: html/cross-origin-embedder-policy/credentialless/resources/dispatcher.js
 SET TIMEOUT: html/editing/dnd/*
 SET TIMEOUT: html/semantics/embedded-content/the-iframe-element/*
 SET TIMEOUT: html/semantics/embedded-content/the-img-element/*
@@ -303,6 +302,7 @@ GENERATE_TESTS: shadow-dom/untriaged/shadow-trees/upper-boundary-encapsulation/w
 
 # Intentional use of setTimeout
 SET TIMEOUT: common/security-features/resources/common.sub.js
+SET TIMEOUT: common/dispatcher/dispatcher.js
 SET TIMEOUT: css/css-fonts/font-display/font-display.html
 SET TIMEOUT: css/css-fonts/font-display/font-display-change.html
 SET TIMEOUT: css/css-fonts/font-display/font-display-change-ref.html
@@ -316,7 +316,6 @@ SET TIMEOUT: html/browsers/windows/auxiliary-browsing-contexts/resources/close-o
 SET TIMEOUT: html/cross-origin-embedder-policy/resources/reporting-worker.js
 SET TIMEOUT: html/cross-origin-opener-policy/navigate-to-aboutblank.https.html
 SET TIMEOUT: html/cross-origin-opener-policy/navigate-top-to-aboutblank.https.html
-SET TIMEOUT: html/cross-origin-opener-policy/resources/dispatcher.js
 SET TIMEOUT: html/dom/documents/dom-tree-accessors/Document.currentScript.html
 SET TIMEOUT: html/webappapis/timers/*
 SET TIMEOUT: orientation-event/resources/orientation-event-helpers.js