DevTools: get rid of the global capabilities set.

Source/devtools/front_end/host/Platform.js

 /*
  * Copyright (C) 2014 Google Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 140 matching lines @@
         WebInspector._monospaceFontFamily = "dejavu sans mono, monospace";
         break;
     case "mac":
         WebInspector._monospaceFontFamily = "Menlo, monospace";
         break;
     case "windows":
         WebInspector._monospaceFontFamily = "Consolas, monospace";
         break;
     }
     return WebInspector._monospaceFontFamily;
-}
+}
+
+/**
+ * @return {boolean}
+ */
+WebInspector.isWorkerFrontend = function()
+{
+    return !!WebInspector.queryParam("dedicatedWorkerId") || !!WebInspector.queryParam("isSharedWorker");
+}