compositor-worker: Create a separate CompositorWorkerGlobalScope for compositor workers.

Source/core/workers/DedicatedWorkerGlobalScope.h

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 23 matching lines @@
 #include "core/dom/MessagePort.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/workers/WorkerGlobalScope.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class DedicatedWorkerThread;
 class WorkerThreadStartupData;
 
-class DedicatedWorkerGlobalScope final : public WorkerGlobalScope {
+class DedicatedWorkerGlobalScope : public WorkerGlobalScope {
     DEFINE_WRAPPERTYPEINFO();
 public:
     typedef WorkerGlobalScope Base;
     static PassRefPtrWillBeRawPtr<DedicatedWorkerGlobalScope> create(DedicatedWorkerThread*, PassOwnPtrWillBeRawPtr<WorkerThreadStartupData>, double timeOrigin);
     virtual ~DedicatedWorkerGlobalScope();
 
     virtual bool isDedicatedWorkerGlobalScope() const override { return true; }
     virtual void countFeature(UseCounter::Feature) const override;
     virtual void countDeprecation(UseCounter::Feature) const override;
 
     // Overridden to allow us to check our pending activity after executing imported script.
     virtual void importScripts(const Vector<String>& urls, ExceptionState&) override;
 
     // EventTarget
     virtual const AtomicString& interfaceName() const override;
 
     void postMessage(ExecutionContext*, PassRefPtr<SerializedScriptValue>, const MessagePortArray*, ExceptionState&);
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(message);
 
     DedicatedWorkerThread* thread() const;
 
     DECLARE_VIRTUAL_TRACE();
 
-private:
+protected:
     DedicatedWorkerGlobalScope(const KURL&, const String& userAgent, DedicatedWorkerThread*, double timeOrigin, const SecurityOrigin*, PassOwnPtrWillBeRawPtr<WorkerClients>);
 };
 
 } // namespace blink
 
 #endif // DedicatedWorkerGlobalScope_h