Tidy up CompositorWorkerManager unit tests.

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 157 matching lines @@
     }
 
     void startAndWaitForInit()
     {
         OwnPtr<WebWaitableEvent> completionEvent = adoptPtr(Platform::current()->createWaitableEvent());
 
         OwnPtr<Vector<CSPHeaderAndType>> headers = adoptPtr(new Vector<CSPHeaderAndType>());
         CSPHeaderAndType headerAndType("contentSecurityPolicy", ContentSecurityPolicyHeaderTypeReport);
         headers->append(headerAndType);
 
+        OwnPtrWillBeRawPtr<WorkerClients> clients = nullptr;
+
         m_workerThread->start(WorkerThreadStartupData::create(
             KURL(ParsedURLString, "http://fake.url/"),
             "fake user agent",
             "//fake source code",
             nullptr,
             DontPauseWorkerGlobalScopeOnStart,
             headers.release(),
             m_securityOrigin.get(),
-            WorkerClients::create(),
+            clients.release(),
             V8CacheOptionsDefault));
         m_workerThread->backingThread().postTask(FROM_HERE, new SignalTask(completionEvent.get()));
         completionEvent->wait();
     }
 
     void postWakeUpTask(long long waitMs)
     {
         WebScheduler* scheduler = m_workerThread->backingThread().platformThread().scheduler();
 
         // The idle task will get posted on an after wake up queue, so we need another task
@@ skipping 90 matching lines @@
 
     completion->wait();
 
     // Make sure doIdleGc has not been called by this stage.
     Mock::VerifyAndClearExpectations(m_workerThread.get());
 
     m_workerThread->terminateAndWait();
 }
 
 } // namespace blink