Avoid referencing an HTMLMediaElement if is currently being deleted

Source/core/html/HTMLMediaElement.cpp

Index: Source/core/html/HTMLMediaElement.cpp
diff --git a/Source/core/html/HTMLMediaElement.cpp b/Source/core/html/HTMLMediaElement.cpp
index 36ad5e5939bd3ff8ffaf03d91db6fb0aaa498ce4..fe4065f1deec6edf5bb6065dc3cfe5d5771fc5ad 100644
--- a/Source/core/html/HTMLMediaElement.cpp
+++ b/Source/core/html/HTMLMediaElement.cpp
@@ -518,9 +518,7 @@ void HTMLMediaElement::scheduleEvent(const AtomicString& eventName)
     LOG(Media, "HTMLMediaElement::scheduleEvent - scheduling '%s'", eventName.string().ascii().data());
 #endif
     RefPtr<Event> event = Event::create(eventName, false, true);
-    event->setTarget(this);
-
-    m_asyncEventQueue->enqueueEvent(event.release());
+    m_asyncEventQueue->enqueueEventWithoutTarget(event.release());

[acolwell GONE FROM CHROMIUM, 2013/05/30 17:08:00]

This doesn't seem right to me. I believe we do want to set the target in most
cases. If ~HTMLMediaElement() has run shouldn't we just avoid scheduling any
events at all? What about  deleting m_asyncEventQueue in the destructor or
adding a m_inDestructor member variable like MediaPlayer has?

 }
 
 void HTMLMediaElement::loadTimerFired(Timer<HTMLMediaElement>*)
@@ -880,8 +878,6 @@ static bool eventTimeCueCompare(const std::pair<double, TextTrackCue*>& a,
 
 void HTMLMediaElement::updateActiveTextTrackCues(double movieTime)
 {
-    LOG(Media, "HTMLMediaElement::updateActiveTextTrackCues");
-
     // 4.8.10.8 Playing the media resource
 
     //  If the current playback position changes while the steps are running,
@@ -890,6 +886,8 @@ void HTMLMediaElement::updateActiveTextTrackCues(double movieTime)
     if (ignoreTrackDisplayUpdateRequests())
         return;
 
+    LOG(Media, "HTMLMediaElement::updateActiveTextTrackCues");
+
     // 1 - Let current cues be a list of cues, initialized to contain all the
     // cues of all the hidden, showing, or showing by default text tracks of the
     // media element (not the disabled ones) whose start times are less than or