Fix data race in blink::WorkerMessagingProxy::reportException

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 e3619d6033acebe5781a0abc24435e0242e03dd5..940daffc482898255ad84265e6826a41b95751ad 100644
--- a/Source/core/workers/WorkerMessagingProxy.cpp
+++ b/Source/core/workers/WorkerMessagingProxy.cpp
@@ -56,6 +56,12 @@ namespace blink {
 
 namespace {
 
+void processExceptionOnWorkerGlobalScope(int exceptionId, bool isHandled, ExecutionContext* scriptContext)
+{
+    WorkerGlobalScope* globalScope = toWorkerGlobalScope(scriptContext);
+    globalScope->exceptionHandled(exceptionId, isHandled);
+}
+
 void processMessageOnWorkerGlobalScope(PassRefPtr<SerializedScriptValue> message, PassOwnPtr<MessagePortChannelArray> channels, WorkerObjectProxy* workerObjectProxy, ExecutionContext* scriptContext)
 {
     WorkerGlobalScope* globalScope = toWorkerGlobalScope(scriptContext);
@@ -166,8 +172,7 @@ void WorkerMessagingProxy::reportException(const String& errorMessage, int lineN
 
     RefPtrWillBeRawPtr<ErrorEvent> event = ErrorEvent::create(errorMessage, sourceURL, lineNumber, columnNumber, nullptr);
     bool errorHandled = !m_workerObject->dispatchEvent(event);
-
-    postTaskToWorkerGlobalScope(createCrossThreadTask(&WorkerGlobalScope::exceptionHandled, m_workerThread->workerGlobalScope(), exceptionId, errorHandled));
+    postTaskToWorkerGlobalScope(createCrossThreadTask(&processExceptionOnWorkerGlobalScope, exceptionId, errorHandled));
 }
 
 void WorkerMessagingProxy::reportConsoleMessage(MessageSource source, MessageLevel level, const String& message, int lineNumber, const String& sourceURL)