Change WokerThread to use a blink::WebThread

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 b1b8b3397dad2086639a47931e92ea877575239f..ccae5ece1dbb78b156bcb931702afe0ce3fbf47b 100644
--- a/Source/core/workers/WorkerMessagingProxy.cpp
+++ b/Source/core/workers/WorkerMessagingProxy.cpp
@@ -115,8 +115,8 @@ void WorkerMessagingProxy::startWorkerGlobalScope(const KURL& scriptURL, const S
     double originTime = document->loader() ? document->loader()->timing()->referenceMonotonicTime() : monotonicallyIncreasingTime();
 
     RefPtr<DedicatedWorkerThread> thread = DedicatedWorkerThread::create(*this, *m_workerObjectProxy.get(), originTime, startupData.release());
-    workerThreadCreated(thread);
     thread->start();
+    workerThreadCreated(thread);
     InspectorInstrumentation::didStartWorkerGlobalScope(m_executionContext.get(), this, scriptURL);
 }