Oilpan: move WorkerGlobalScope to oilpan's heap.

Source/core/workers/WorkerGlobalScope.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright (C) 2009, 2011 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 75 matching lines @@
     , m_timeOrigin(timeOrigin)
 {
     ScriptWrappable::init(this);
     setClient(this);
     setSecurityOrigin(SecurityOrigin::create(url));
     m_workerClients->reattachThread();
 }
 
 WorkerGlobalScope::~WorkerGlobalScope()
 {
-    ASSERT(thread()->isCurrentThread());
-
-    // Notify proxy that we are going away. This can free the WorkerThread object, so do not access it after this.
-    thread()->workerReportingProxy().workerGlobalScopeDestroyed();
-
-    setClient(0);
+#if !ENABLE(OILPAN)
+    dispose();
+#endif
 }
 
 void WorkerGlobalScope::applyContentSecurityPolicyFromString(const String& policy, ContentSecurityPolicyHeaderType contentSecurityPolicyType)
 {
     setContentSecurityPolicy(ContentSecurityPolicy::create(this));
     contentSecurityPolicy()->didReceiveHeader(policy, contentSecurityPolicyType, ContentSecurityPolicyHeaderSourceHTTP);
 }
 
 ExecutionContext* WorkerGlobalScope::executionContext() const
 {
@@ skipping 71 matching lines @@
 void WorkerGlobalScope::postTask(PassOwnPtr<ExecutionContextTask> task)
 {
     thread()->runLoop().postTask(task);
 }
 
 void WorkerGlobalScope::clearInspector()
 {
     m_workerInspectorController.clear();
 }
 
+void WorkerGlobalScope::dispose()
+{
+    ASSERT(thread()->isCurrentThread());
+
+    // Notify proxy that we are going away. This can free the WorkerThread object, so do not access it after this.
+    thread()->workerReportingProxy().workerGlobalScopeDestroyed();
+
+    clearScript();
+    clearInspector();
+    setClient(0);
+    // NOTE: the thread reference isn't cleared, as the execution context's
+    // thread is accessed by other GCed objects being finalized/destructed.

[haraken, 2014/03/10 07:10:03]

Thanks sof for the clarification! Now I think this CL is almost ready to go.

Let me ask a final question: Why is it OK to not clear m_thread in
WorkerGlobalScope::dispose()? It looks strange that WorkerThread is disposing
WorkerGlobalScope but WorkerGlobalScope does not (intentionally) clear the raw
pointer to the WorkerThread. I do understand why you cannot clear m_thread, but
it looks strange that you cannot clear m_thread.

[Mads Ager (chromium), 2014/03/10 08:51:14]

Is the issue here that lifecycle observers will access this object until the
destructor has been called? If that is the only issue this is working as it
should and the comment should be updated to state that m_thread can be accessed
by context life cycle observers until the WorkerGlobalScope is destructed.

The other option, which might be clearer, would be to make it possible to notify
the observers that the context is gone at this point by explicitly clearing the
observers in the lifecycle notifier. Long term, the context observers should
directly use our weak pointers instead, but we need to deal with this manually
for now until we get Document into the heap as well.

I think it would be fine to land this with the comment updated if the lifecycle
observers are the only ones accessing m_thread.

+}
+
 void WorkerGlobalScope::importScripts(const Vector<String>& urls, ExceptionState& exceptionState)
 {
     ASSERT(contentSecurityPolicy());
     Vector<String>::const_iterator urlsEnd = urls.end();
     Vector<KURL> completedURLs;
     for (Vector<String>::const_iterator it = urls.begin(); it != urlsEnd; ++it) {
         const KURL& url = executionContext()->completeURL(*it);
         if (!url.isValid()) {
             exceptionState.throwDOMException(SyntaxError, "The URL '" + *it + "' is invalid.");
             return;
@@ skipping 71 matching lines @@
 bool WorkerGlobalScope::idleNotification()
 {
     return script()->idleNotification();
 }
 
 WorkerEventQueue* WorkerGlobalScope::eventQueue() const
 {
     return m_eventQueue.get();
 }
 
+void WorkerGlobalScope::trace(Visitor* visitor)
+{
+    visitor->trace(m_console);
+    visitor->trace(m_location);
+    visitor->trace(m_navigator);
+    WillBeHeapSupplementable<WorkerGlobalScope>::trace(visitor);
+}
+
 } // namespace WebCore