compositor-worker: Get the thread to run compositor-workers from the Platform.

Source/core/workers/WorkerThreadTest.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 "core/workers/WorkerThread.h"
 
 #include "core/inspector/ConsoleMessage.h"
 #include "core/workers/WorkerReportingProxy.h"
 #include "core/workers/WorkerThreadStartupData.h"
@@ skipping 87 matching lines @@
         WorkerReportingProxy& mockWorkerReportingProxy)
         : WorkerThread(WorkerLoaderProxy::create(mockWorkerLoaderProxyProvider), mockWorkerReportingProxy)
         , m_thread(WebThreadSupportingGC::create("Test thread"))
         , m_scriptLoadedEvent(adoptPtr(Platform::current()->createWaitableEvent()))
     {
     }
 
     ~WorkerThreadForTest() override { }
 
     // WorkerThread implementation:
-    WebThreadSupportingGC& backingThread() override
+    WebThread& backingThread() override
     {
-        return *m_thread;
+        return m_thread->platformThread();
     }
 
     MOCK_METHOD1(doIdleGc, bool(double deadlineSeconds));
 
     PassRefPtrWillBeRawPtr<WorkerGlobalScope> createWorkerGlobalScope(PassOwnPtr<WorkerThreadStartupData> startupData) override
     {
         return adoptRefWillBeNoop(new FakeWorkerGlobalScope(startupData->m_scriptURL, startupData->m_userAgent, this, startupData->m_starterOrigin, startupData->m_workerClients.release()));
     }
 
     void waitUntilScriptLoaded()
@@ skipping 196 matching lines @@
 TEST_F(WorkerThreadTest, GcDoesNotOccurWhenNotIdle)
 {
     OwnPtr<WebWaitableEvent> completion = adoptPtr(Platform::current()->createWaitableEvent());
 
     EXPECT_CALL(*m_workerThread, doIdleGc(_)).Times(0);
 
     expectWorkerLifetimeReportingCalls();
     start();
     waitForInit();
 
-    WebScheduler* scheduler = m_workerThread->backingThread().platformThread().scheduler();
+    WebScheduler* scheduler = m_workerThread->backingThread().scheduler();
 
     // Post a repeating task that should prevent any GC from happening.
     scheduler->postLoadingTask(FROM_HERE, new RepeatingTask(scheduler, completion.get()));
 
     completion->wait();
 
     // Make sure doIdleGc has not been called by this stage.
     Mock::VerifyAndClearExpectations(m_workerThread.get());
 
     m_workerThread->terminateAndWait();
 }
 
 } // namespace blink