ServiceWorker: Bypass resolving a promise when ExecutionContext is gone

Source/modules/serviceworkers/ServiceWorker.cpp

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 138 matching lines @@
     if (existingServiceWorker) {
         ASSERT(existingServiceWorker->executionContext() == executionContext);
         return existingServiceWorker;
     }
 
     return create(executionContext, adoptPtr(worker));
 }
 
 PassRefPtrWillBeRawPtr<ServiceWorker> ServiceWorker::from(ScriptPromiseResolver* resolver, WebType* worker)
 {
+    if (resolver->scriptState()->contextIsEmpty()) {

[haraken, 2014/07/17 07:53:36]

Shouldn't this check be if(!resolver->scriptState->executionContext()) ?

It's possible that a V8 context is not empty but the execution context is gone.
I guess what we want to check here is to check the existence of the execution
context.

[nhiroki, 2014/07/17 08:30:02]

ScriptState::executionContext() refers to V8::Context and it crashes if the v8
context is empty. Should we check an existence of the v8 context in
ScriptState::executionContext() ...?

+        if (worker && !worker->proxy())
+            delete worker;

[haraken, 2014/07/17 07:53:36]

I don't understand the memory management here either...

+        return nullptr;
+    }
+
     RefPtrWillBeRawPtr<ServiceWorker> serviceWorker = ServiceWorker::from(resolver->scriptState()->executionContext(), worker);
     ScriptState::Scope scope(resolver->scriptState());
     serviceWorker->waitOnPromise(resolver->promise());
     return serviceWorker;
 }
 
 void ServiceWorker::setProxyState(ProxyState state)
 {
     if (m_proxyState == state)
         return;
@@ skipping 63 matching lines @@
     , WebServiceWorkerProxy(this)
     , m_outerWorker(worker)
     , m_proxyState(Initial)
 {
     ScriptWrappable::init(this);
     ASSERT(m_outerWorker);
     m_outerWorker->setProxy(this);
 }
 
 } // namespace WebCore