Oilpan: add transition types to track interface objects.

Source/core/html/track/vtt/VTTParser.h

Index: Source/core/html/track/vtt/VTTParser.h
diff --git a/Source/core/html/track/vtt/VTTParser.h b/Source/core/html/track/vtt/VTTParser.h
index 93170e1b81bd5f38c1cb0a310e48c6029160b0df..7c94845bfd9a2db994df2df2dcb1fb0310f1b07f 100644
--- a/Source/core/html/track/vtt/VTTParser.h
+++ b/Source/core/html/track/vtt/VTTParser.h
@@ -39,6 +39,7 @@
 #include "core/html/track/vtt/VTTCue.h"
 #include "core/html/track/vtt/VTTRegion.h"
 #include "core/html/track/vtt/VTTTokenizer.h"
+#include "platform/heap/Handle.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/text/StringBuilder.h"
 
@@ -56,7 +57,7 @@ public:
     virtual void fileFailedToParse() = 0;
 };
 
-class VTTParser FINAL {
+class VTTParser FINAL : public NoBaseWillBeGarbageCollectedFinalized<VTTParser> {
 public:
     enum ParseState {
         Initial,
@@ -67,9 +68,9 @@ public:
         BadCue
     };
 
-    static PassOwnPtr<VTTParser> create(VTTParserClient* client, Document& document)
+    static PassOwnPtrWillBeRawPtr<VTTParser> create(VTTParserClient* client, Document& document)
     {
-        return adoptPtr(new VTTParser(client, document));
+        return adoptPtrWillBeNoop(new VTTParser(client, document));
     }
 
     static inline bool isRecognizedTag(const AtomicString& tagName)
@@ -105,8 +106,10 @@ public:
     void flush();
 
     // Transfers ownership of last parsed cues to caller.
-    void getNewCues(Vector<RefPtr<VTTCue> >&);
-    void getNewRegions(Vector<RefPtr<VTTRegion> >&);
+    void getNewCues(WillBeHeapVector<RefPtrWillBeMember<VTTCue> >&);
+    void getNewRegions(WillBeHeapVector<RefPtrWillBeMember<VTTRegion> >&);
+
+    void trace(Visitor*);
 
 private:
     VTTParser(VTTParserClient*, Document&);
@@ -141,9 +144,9 @@ private:
 
     VTTParserClient* m_client;

[haraken, 2014/04/21 01:30:54]

Let me confirm: The VTTParser object can outlive the client object (because the
VTTParser object is on-heap but the client object is off-heap), but it's not
possible that methods of the VTTParser object are called after the client object
dies (because the VTTParser object is owned by the client). Thus using a raw
pointer for m_client is safe here. Right?

[sof, 2014/04/21 15:23:42]

That is correct; TextTrackLoader is the only client, and it keeps a persistent
reference to VTTParser. Hence, it is simply not possible for the VTTParser to be
accessed after the loader (==client) goes away.

Actually, we can do better and avoid this persistent reference -- I had
overlooked that LoadableTextTrack (TextTrackLoader's only owner) is also a GCed
object, so we can move the loader to the heap also. Updated patch to do so.

 
-    Vector<RefPtr<VTTCue> > m_cuelist;
+    WillBeHeapVector<RefPtrWillBeMember<VTTCue> > m_cueList;
 
-    Vector<RefPtr<VTTRegion> > m_regionList;
+    WillBeHeapVector<RefPtrWillBeMember<VTTRegion> > m_regionList;
 };
 
 } // namespace WebCore