Use C++11 features in core/workers.

Source/core/workers/Worker.cpp

 /*
  * Copyright (C) 2008, 2010 Apple Inc. All Rights Reserved.
  * 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:
  * 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 27 matching lines @@
 #include "core/workers/WorkerGlobalScopeProxy.h"
 #include "core/workers/WorkerGlobalScopeProxyProvider.h"
 #include "core/workers/WorkerScriptLoader.h"
 #include "core/workers/WorkerThread.h"
 #include "wtf/MainThread.h"
 
 namespace blink {
 
 inline Worker::Worker(ExecutionContext* context)
     : AbstractWorker(context)
-    , m_contextProxy(0)
+    , m_contextProxy(nullptr)
 {
 }
 
 PassRefPtrWillBeRawPtr<Worker> Worker::create(ExecutionContext* context, const String& url, ExceptionState& exceptionState)
 {
     ASSERT(isMainThread());
     Document* document = toDocument(context);
     UseCounter::count(context, UseCounter::WorkerStart);
     if (!document->page()) {
         exceptionState.throwDOMException(InvalidAccessError, "The context provided is invalid.");
@@ skipping 76 matching lines @@
     }
     m_scriptLoader = nullptr;
 }
 
 void Worker::trace(Visitor* visitor)
 {
     AbstractWorker::trace(visitor);
 }
 
 } // namespace blink