Revert of compositor-worker: Share a thread and an isolate for compositor workers.

Source/modules/compositorworker/CompositorWorkerThread.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "modules/compositorworker/CompositorWorkerThread.h"
 
 #include "bindings/core/v8/V8Initializer.h"
 #include "core/workers/WorkerObjectProxy.h"
 #include "core/workers/WorkerThreadStartupData.h"
 #include "modules/compositorworker/CompositorWorkerGlobalScope.h"
-#include "modules/compositorworker/CompositorWorkerManager.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 PassRefPtr<CompositorWorkerThread> CompositorWorkerThread::create(PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, WorkerObjectProxy& workerObjectProxy, double timeOrigin)
 {
     ASSERT(isMainThread());
     return adoptRef(new CompositorWorkerThread(workerLoaderProxy, workerObjectProxy, timeOrigin));
 }
 
 CompositorWorkerThread::CompositorWorkerThread(PassRefPtr<WorkerLoaderProxy> workerLoaderProxy, WorkerObjectProxy& workerObjectProxy, double timeOrigin)
     : WorkerThread(workerLoaderProxy, workerObjectProxy)
     , m_workerObjectProxy(workerObjectProxy)
     , m_timeOrigin(timeOrigin)
 {
 }
 
 CompositorWorkerThread::~CompositorWorkerThread()
 {
 }
 
 PassRefPtrWillBeRawPtr<WorkerGlobalScope> CompositorWorkerThread::createWorkerGlobalScope(PassOwnPtr<WorkerThreadStartupData> startupData)
 {
     return CompositorWorkerGlobalScope::create(this, startupData, m_timeOrigin);
 }
 
 WebThreadSupportingGC& CompositorWorkerThread::backingThread()
 {
-    return CompositorWorkerManager::instance()->compositorWorkerThread();
-}
-
-void CompositorWorkerThread::initializeBackingThread()
-{
-    CompositorWorkerManager::instance()->initializeBackingThread();
-}
-
-void CompositorWorkerThread::shutdownBackingThread()
-{
-    CompositorWorkerManager::instance()->shutdownBackingThread();
-}
-
-v8::Isolate* CompositorWorkerThread::initializeIsolate()
-{
-    return CompositorWorkerManager::instance()->initializeIsolate();
-}
-
-void CompositorWorkerThread::willDestroyIsolate()
-{
-    CompositorWorkerManager::instance()->willDestroyIsolate();
-}
-
-void CompositorWorkerThread::destroyIsolate()
-{
-    CompositorWorkerManager::instance()->destroyIsolate();
-}
-
-void CompositorWorkerThread::terminateV8Execution()
-{
-    CompositorWorkerManager::instance()->terminateV8Execution();
+    if (!m_thread)
+        m_thread = WebThreadSupportingGC::create("CompositorWorker Thread");
+    return *m_thread.get();
 }
 
 } // namespace blink