Oilpan: Prepare to move EventQueue and its subclasses to Oilpan heap.

Source/core/html/track/TextTrackList.cpp

Index: Source/core/html/track/TextTrackList.cpp
diff --git a/Source/core/html/track/TextTrackList.cpp b/Source/core/html/track/TextTrackList.cpp
index 15df7569e1aa15364a8051a1f69b4a4f54a180fe..0738c95e7bac2388d6d0068042ba734fc8a20251 100644
--- a/Source/core/html/track/TextTrackList.cpp
+++ b/Source/core/html/track/TextTrackList.cpp
@@ -47,9 +47,12 @@ TextTrackList::~TextTrackList()
 {
 #if !ENABLE(OILPAN)
     ASSERT(!m_owner);
-#endif
+
+    // TextTrackList and m_asyncEventQueue always become unreachable
+    // together. So TextTrackList and m_asyncEventQueue are destructed in the
+    // same GC. We don't need to close it explicitly in Oilpan.
     m_asyncEventQueue->close();

[haraken, 2014/06/12 10:48:51]

In non-oilpan builds, some destructors call close(), some destructors call
cancelAllEvents(), and some destructors do nothing. I think we need to do
nothing, because destroying OwnPtr<EventQueue> will gracefully clean up the
EventQueue.

So I think you can just remove close() and cancelAllEvents() from these
destructors instead of moving them to #if !ENABLE(OILPAN). However, I'm OK with
your CL to keep the current non-oilpan code as is.

[tkent, 2014/06/12 23:50:12]

I'd like to keep non-oilpan code.

-#if !ENABLE(OILPAN)
+
     for (unsigned i = 0; i < length(); ++i) {
         item(i)->setTrackList(0);
     }
@@ -334,6 +337,7 @@ HTMLMediaElement* TextTrackList::owner() const
 void TextTrackList::trace(Visitor* visitor)
 {
     visitor->trace(m_owner);
+    visitor->trace(m_asyncEventQueue);
     visitor->trace(m_addTrackTracks);
     visitor->trace(m_elementTracks);
     visitor->trace(m_inbandTracks);