Turn WorkerLoaderProxy into a threadsafe, ref-counted object.

Source/core/workers/WorkerMessagingProxy.cpp

Index: Source/core/workers/WorkerMessagingProxy.cpp
diff --git a/Source/core/workers/WorkerMessagingProxy.cpp b/Source/core/workers/WorkerMessagingProxy.cpp
index d6352bcac522d9e0f59d1b7582d3954e54fb34aa..8935d1144f997f59df403a62bd573fbf15dcd266 100644
--- a/Source/core/workers/WorkerMessagingProxy.cpp
+++ b/Source/core/workers/WorkerMessagingProxy.cpp
@@ -106,6 +106,8 @@ WorkerMessagingProxy::~WorkerMessagingProxy()
     ASSERT(!m_workerObject);
     ASSERT((m_executionContext->isDocument() && isMainThread())
         || (m_executionContext->isWorkerGlobalScope() && toWorkerGlobalScope(m_executionContext.get())->thread()->isCurrentThread()));
+    if (m_loaderProxy)
+        m_loaderProxy->detachProvider(this);
 }
 
 void WorkerMessagingProxy::startWorkerGlobalScope(const KURL& scriptURL, const String& userAgent, const String& sourceCode, WorkerThreadStartMode startMode)
@@ -122,7 +124,8 @@ void WorkerMessagingProxy::startWorkerGlobalScope(const KURL& scriptURL, const S
     OwnPtrWillBeRawPtr<WorkerThreadStartupData> startupData = WorkerThreadStartupData::create(scriptURL, userAgent, sourceCode, startMode, document->contentSecurityPolicy()->deprecatedHeader(), document->contentSecurityPolicy()->deprecatedHeaderType(), starterOrigin, m_workerClients.release());
     double originTime = document->loader() ? document->loader()->timing()->referenceMonotonicTime() : monotonicallyIncreasingTime();
 
-    RefPtr<DedicatedWorkerThread> thread = DedicatedWorkerThread::create(*this, *m_workerObjectProxy.get(), originTime, startupData.release());
+    m_loaderProxy = WorkerLoaderProxy::create(this);
+    RefPtr<DedicatedWorkerThread> thread = DedicatedWorkerThread::create(m_loaderProxy, *m_workerObjectProxy.get(), originTime, startupData.release());
     thread->start();
     workerThreadCreated(thread);
     m_workerInspectorProxy->workerThreadCreated(m_executionContext.get(), m_workerThread.get(), scriptURL);