Unset CompositorWorkerGlobalScope during WorkerGlobalScope::dipose.

third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp

Index: third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp
diff --git a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp
index 60cba6a5e183d457422072ffdbf0eb0d9f385087..5b27d95df1fdbc916dcfd7a32ada05b38eb3b842 100644
--- a/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp
+++ b/third_party/WebKit/Source/modules/compositorworker/CompositorWorkerGlobalScope.cpp
@@ -49,6 +49,14 @@ const AtomicString& CompositorWorkerGlobalScope::interfaceName() const
     return EventTargetNames::CompositorWorkerGlobalScope;
 }
 
+void CompositorWorkerGlobalScope::removeAllEventListeners()
+{
+    // Note, we may still have callbacks in m_callbackCollection, but this
+    // ensures that we will no longer try to call them after this global
+    // scope has been disposed.
+    CompositorProxyClient::from(clients())->setGlobalScope(nullptr);
+}
+
 void CompositorWorkerGlobalScope::postMessage(ExecutionContext* executionContext, PassRefPtr<SerializedScriptValue> message, const MessagePortArray& ports, ExceptionState& exceptionState)
 {
     // Disentangle the port in preparation for sending it to the remote context.