Oilpan: add transition types to track interface objects.

Source/core/html/HTMLMediaElement.h

Index: Source/core/html/HTMLMediaElement.h
diff --git a/Source/core/html/HTMLMediaElement.h b/Source/core/html/HTMLMediaElement.h
index 1e26615e8796c22ba961631ab64714a8686e4e4b..9e0f91d81385cdc2be8a689a3becabc39b8039e5 100644
--- a/Source/core/html/HTMLMediaElement.h
+++ b/Source/core/html/HTMLMediaElement.h
@@ -163,9 +163,9 @@ public:
     bool togglePlayStateWillPlay() const;
     void togglePlayState();
 
-    PassRefPtr<TextTrack> addTextTrack(const AtomicString& kind, const AtomicString& label, const AtomicString& language, ExceptionState&);
-    PassRefPtr<TextTrack> addTextTrack(const AtomicString& kind, const AtomicString& label, ExceptionState& exceptionState) { return addTextTrack(kind, label, emptyAtom, exceptionState); }
-    PassRefPtr<TextTrack> addTextTrack(const AtomicString& kind, ExceptionState& exceptionState) { return addTextTrack(kind, emptyAtom, emptyAtom, exceptionState); }
+    PassRefPtrWillBeRawPtr<TextTrack> addTextTrack(const AtomicString& kind, const AtomicString& label, const AtomicString& language, ExceptionState&);
+    PassRefPtrWillBeRawPtr<TextTrack> addTextTrack(const AtomicString& kind, const AtomicString& label, ExceptionState& exceptionState) { return addTextTrack(kind, label, emptyAtom, exceptionState); }
+    PassRefPtrWillBeRawPtr<TextTrack> addTextTrack(const AtomicString& kind, ExceptionState& exceptionState) { return addTextTrack(kind, emptyAtom, emptyAtom, exceptionState); }
 
     TextTrackList* textTracks();
     CueList currentlyActiveCues() const { return m_currentlyActiveCues; }
@@ -186,10 +186,12 @@ public:
     // FIXME: Remove this when WebMediaPlayerClientImpl::loadInternal does not depend on it.
     virtual KURL mediaPlayerPosterURL() OVERRIDE { return KURL(); }
 
-    struct TrackGroup {
+    class TrackGroup {
+        STACK_ALLOCATED();
+    public:
         enum GroupKind { CaptionsAndSubtitles, Description, Chapter, Metadata, Other };
 
-        TrackGroup(GroupKind kind)
+        explicit TrackGroup(GroupKind kind)
             : visibleTrack(nullptr)
             , defaultTrack(nullptr)
             , kind(kind)
@@ -197,9 +199,9 @@ public:
         {
         }
 
-        Vector<RefPtr<TextTrack> > tracks;
-        RefPtr<TextTrack> visibleTrack;
-        RefPtr<TextTrack> defaultTrack;
+        WillBeHeapVector<RefPtrWillBeMember<TextTrack> > tracks;
+        RefPtrWillBeMember<TextTrack> visibleTrack;
+        RefPtrWillBeMember<TextTrack> defaultTrack;
         GroupKind kind;
         bool hasSrcLang;
     };
@@ -221,8 +223,8 @@ public:
     void textTrackModeChanged(TextTrack*);
     void textTrackAddCues(TextTrack*, const TextTrackCueList*);
     void textTrackRemoveCues(TextTrack*, const TextTrackCueList*);
-    void textTrackAddCue(TextTrack*, PassRefPtr<TextTrackCue>);
-    void textTrackRemoveCue(TextTrack*, PassRefPtr<TextTrackCue>);
+    void textTrackAddCue(TextTrack*, PassRefPtrWillBeRawPtr<TextTrackCue>);
+    void textTrackRemoveCue(TextTrack*, PassRefPtrWillBeRawPtr<TextTrackCue>);
 
     // EventTarget function.
     // Both Node (via HTMLElement) and ActiveDOMObject define this method, which
@@ -502,8 +504,8 @@ private:
     bool m_processingPreferenceChange : 1;
     double m_lastTextTrackUpdateTime;
 
-    RefPtr<TextTrackList> m_textTracks;
-    Vector<RefPtr<TextTrack> > m_textTracksWhenResourceSelectionBegan;
+    RefPtrWillBePersistent<TextTrackList> m_textTracks;

[Mads Ager (chromium), 2014/04/22 10:33:25]

HTMLMediaElement is in the Oilpan heap and there is a trace method. Please use
Member here and trace it (which might lead to finalization-order changes, so we
need to be careful that the TextTrackList destructor does not touch the
HTMLMediaElement.)

[haraken, 2014/04/22 10:40:03]

Good point. I forgot that the Node hierarchy is already on the heap.

Probably do we need to implement a complete trace chain first?

[sof, 2014/04/22 12:44:01]

Already in place; switched to Persistent + removed the explicit clearing of the
tracklist as a result.

+    WillBePersistentHeapVector<RefPtrWillBeMember<TextTrack> > m_textTracksWhenResourceSelectionBegan;

[Mads Ager (chromium), 2014/04/22 10:33:25]

Remove the Persistent here as well and just make it a WillBeHeapVector and trace
it. Again, we need to double-check the TextTrack destructor.

[sof, 2014/04/22 12:44:01]

I've gone through the destructors, and apart from InbandTextTrack notifying the
client, they're all empty now.

 
     CueIntervalTree m_cueTree;