Oilpan: Prpare to move WorkerEventQueue to Oilpan heap.

Source/core/workers/WorkerEventQueue.cpp

 /*
  * Copyright (C) 2010 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 15 matching lines @@
 
 #include "config.h"
 #include "core/workers/WorkerEventQueue.h"
 
 #include "core/dom/ExecutionContext.h"
 #include "core/dom/ExecutionContextTask.h"
 #include "core/events/Event.h"
 
 namespace WebCore {
 
-PassOwnPtr<WorkerEventQueue> WorkerEventQueue::create(ExecutionContext* context)
+PassOwnPtrWillBeRawPtr<WorkerEventQueue> WorkerEventQueue::create(ExecutionContext* context)
 {
-    return adoptPtr(new WorkerEventQueue(context));
+    return adoptPtrWillBeNoop(new WorkerEventQueue(context));
 }
 
 WorkerEventQueue::WorkerEventQueue(ExecutionContext* context)
     : m_executionContext(context)
     , m_isClosed(false)
 {
 }
 
 WorkerEventQueue::~WorkerEventQueue()
 {
+#if !ENABLE(OILPAN)
     close();

[haraken, 2014/05/30 12:10:41]

I'm not sure if you can remove close() from the destructor. If you don't call
it, task->cancel() is not called. Then the task is not unregistered from the
WorkerEventQueue, and thus it's possible that
m_eventQueue->removeEvent(m_event.get()) at line 81 is executed after the
WorkerEventQueue is destructed.

An ideal solution would be to move ExecutionContextTask (from which
EventDispatcherTask is derived) to the heap and use Members for
EventDispatcherTask::m_event and EventDispatcherTask::m_eventQueue. However, it
looks a bit hard to move ExecutionContextTask to the heap (probably only for me
who doesn't have much template knowledge).....

[tkent, 2014/05/30 13:47:58]

In this patch, I moved this |close()| callsite to WorkerGlobalScope::dispose
because we should not touch on-heap object in the destructor.

[haraken, 2014/05/30 14:00:56]

oh, I missed that. That makes sense.

+#endif
+}
+
+void WorkerEventQueue::trace(Visitor* visitor)
+{
+    visitor->trace(m_eventTaskMap);
 }
 
 class WorkerEventQueue::EventDispatcherTask : public ExecutionContextTask {
 public:
     static PassOwnPtr<EventDispatcherTask> create(PassRefPtrWillBeRawPtr<Event> event, WorkerEventQueue* eventQueue)
     {
         return adoptPtr(new EventDispatcherTask(event, eventQueue));
     }
 
     virtual ~EventDispatcherTask()
@@ skipping 65 matching lines @@
 {
     m_isClosed = true;
     for (EventTaskMap::iterator it = m_eventTaskMap.begin(); it != m_eventTaskMap.end(); ++it) {
         EventDispatcherTask* task = it->value;
         task->cancel();
     }
     m_eventTaskMap.clear();
 }
 
 }