Oilpan: Use transition types for HTMLMediaElement and make AudioSourceProviderClient a GC mixin.

Source/core/html/HTMLMediaElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple 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 266 matching lines @@
     , m_tracksAreReady(true)
     , m_haveVisibleTextTrack(false)
     , m_processingPreferenceChange(false)
 #if ENABLE(OILPAN)
     , m_isFinalizing(false)
 #endif
     , m_lastTextTrackUpdateTime(-1)
     , m_textTracks(nullptr)
     , m_ignoreTrackDisplayUpdate(0)
 #if ENABLE(WEB_AUDIO)
-    , m_audioSourceNode(0)
+    , m_audioSourceNode(nullptr)
 #endif
 {
     ASSERT(RuntimeEnabledFeatures::mediaEnabled());
 
     WTF_LOG(Media, "HTMLMediaElement::HTMLMediaElement");
     ScriptWrappable::init(this);
 
     if (document.settings() && document.settings()->mediaPlaybackRequiresUserGesture())
         m_userGestureRequiredForPlay = true;
 
@@ skipping 67 matching lines @@
     // supplementable table.)  Handled for now by entering an
     // is-finalizing state, which is explicitly checked for if the
     // player tries to access the media element during shutdown.
     //
     // FIXME: Oilpan: move the media player to the heap instead and
     // avoid having to finalize it from here; this whole #if block
     // could then be removed (along with the state bit it depends on.)
     // crbug.com/378229
     m_isFinalizing = true;
 #endif
-    clearMediaPlayerAndAudioSourceProviderClient();
+
+    // The m_audioSourceNode is either dead already or it is dying together with
+    // this HTMLMediaElement which it strongly keeps alive.
+#if !ENABLE(OILPAN)
+    ASSERT(!m_audioSourceNode);
+#endif
+    clearMediaPlayerAndAudioSourceProviderClientWithoutLocking();
 
 #if !ENABLE(OILPAN)
     document().decrementLoadEventDelayCount();
 #endif
 }
 
 void HTMLMediaElement::didMoveToNewDocument(Document& oldDocument)
 {
     WTF_LOG(Media, "HTMLMediaElement::didMoveToNewDocument");
 
@@ skipping 2726 matching lines @@
 
     // 6 - Abort the overall resource selection algorithm.
     m_currentSourceNode = nullptr;
 
     // Reset m_readyState since m_player is gone.
     m_readyState = HAVE_NOTHING;
     updateMediaController();
     updateActiveTextTrackCues(0);
 }
 
-void HTMLMediaElement::clearMediaPlayerAndAudioSourceProviderClient()
+void HTMLMediaElement::clearMediaPlayerAndAudioSourceProviderClientWithoutLocking()
 {
 #if ENABLE(WEB_AUDIO)
-    if (m_audioSourceNode)
-        m_audioSourceNode->lock();
-
     if (audioSourceProvider())
         audioSourceProvider()->setClient(0);
 #endif
-
     m_player.clear();
-
-#if ENABLE(WEB_AUDIO)
-    if (m_audioSourceNode)
-        m_audioSourceNode->unlock();
-#endif
 }
 
 void HTMLMediaElement::clearMediaPlayer(int flags)
 {
     forgetResourceSpecificTracks();
 
     closeMediaSource();
 
     m_delayingLoadForPreloadNone = false;
 
-    clearMediaPlayerAndAudioSourceProviderClient();
+#if ENABLE(WEB_AUDIO)
+    if (m_audioSourceNode)
+        m_audioSourceNode->lock();
+#endif
+
+    clearMediaPlayerAndAudioSourceProviderClientWithoutLocking();
+
+#if ENABLE(WEB_AUDIO)
+    if (m_audioSourceNode)
+        m_audioSourceNode->unlock();
+#endif
 
     stopPeriodicTimers();
     m_loadTimer.stop();
 
     m_pendingActionFlags &= ~flags;
     m_loadState = WaitingForSource;
 
     if (m_textTracks)
         configureTextTrackDisplay(AssumeNoVisibleChange);
 }
@@ skipping 490 matching lines @@
     HTMLElement::defaultEventHandler(event);
 }
 
 void HTMLMediaElement::trace(Visitor* visitor)
 {
     visitor->trace(m_error);
     visitor->trace(m_currentSourceNode);
     visitor->trace(m_nextChildNodeToConsider);
     visitor->trace(m_textTracks);
     visitor->trace(m_textTracksWhenResourceSelectionBegan);
+    visitor->registerWeakMembers<HTMLMediaElement, &HTMLMediaElement::clearWeakMembers>(this);
     WillBeHeapSupplementable<HTMLMediaElement>::trace(visitor);
     HTMLElement::trace(visitor);
 }
 
+void HTMLMediaElement::clearWeakMembers(Visitor* visitor)
+{
+    if (!visitor->isAlive(m_audioSourceNode) && audioSourceProvider())
+        audioSourceProvider()->setClient(0);

[haraken, 2014/06/11 01:19:49]

This looks OK but it would be better to just call setAudioSourceNode:

  if (!visitor->isAlive(m_audioSourceNode))
    setAudioSourceNode(0);

[zerny-chromium, 2014/06/11 06:26:57]

I don't think so, since m_audioSourceNode is dying and setAudioSourceNode would
do a ref (via lock).

 }
+
+}