firefox: userChrome utilize path

Supported in nix-community/home-manager#6761 We
can use the path to also copy the images over to the proper location, as
well.

Author: khaneliman

modules/home/programs/graphical/browsers/firefox/default.nix

@@ -63,22 +63,6 @@ in
   };
 
   config = mkIf cfg.enable {
-    home.file =
-      let
-        firefoxPath =
-          if pkgs.stdenv.hostPlatform.isLinux then
-            ".mozilla/firefox/${config.${namespace}.user.name}"
-          else
-            "/Users/${config.${namespace}.user.name}/Library/Application Support/Firefox/Profiles/${config.${namespace}.user.name}";
-      in
-      {
-        "${firefoxPath}/chrome/img" = {
-          source = lib.cleanSourceWith { src = lib.cleanSource ./chrome/img/.; };
-
-          recursive = true;
-        };
-      };
-
     programs.firefox = {
       enable = true;
       package = if pkgs.stdenv.hostPlatform.isLinux then pkgs.firefox-devedition else null;
@@ -165,7 +149,7 @@ in
           ];
 
           # TODO: support alternative theme loading
-          userChrome = ./chrome/userChrome.css;
+          userChrome = ./chrome;
         };
       };
     };