Tidy up MediaStreamSource details.

third_party/WebKit/Source/platform/mediastream/MediaStreamSource.h

Index: third_party/WebKit/Source/platform/mediastream/MediaStreamSource.h
diff --git a/third_party/WebKit/Source/platform/mediastream/MediaStreamSource.h b/third_party/WebKit/Source/platform/mediastream/MediaStreamSource.h
index 3939e1245f4abd2556df04e9daa21dc1266eef05..ebc1852c9db560eacd8ace85fbe31f438b4766c7 100644
--- a/third_party/WebKit/Source/platform/mediastream/MediaStreamSource.h
+++ b/third_party/WebKit/Source/platform/mediastream/MediaStreamSource.h
@@ -45,7 +45,6 @@
 namespace blink {
 
 class PLATFORM_EXPORT MediaStreamSource final : public GarbageCollectedFinalized<MediaStreamSource> {
-    USING_PRE_FINALIZER(MediaStreamSource, dispose);
 public:
     class PLATFORM_EXPORT Observer : public GarbageCollectedMixin {
     public:
@@ -54,6 +53,7 @@ public:
     };
 
     class ExtraData {
+        USING_FAST_MALLOC(ExtraData);
     public:
         virtual ~ExtraData() { }
     };
@@ -70,7 +70,6 @@ public:
     };
 
     static MediaStreamSource* create(const String& id, StreamType, const String& name, bool remote, ReadyState = ReadyStateLive, bool requiresConsumer = false);
-    void dispose();
 
     const String& id() const { return m_id; }
     StreamType type() const { return m_type; }
@@ -96,6 +95,9 @@ public:
     bool removeAudioConsumer(AudioDestinationConsumer*);
     const HeapHashSet<Member<AudioDestinationConsumer>>& audioConsumers() { return m_audioConsumers; }
 
+    // |m_extraData| may hold pointers to GC objects, and it may touch them in destruction.
+    // So this class is eagerly finalized to finalize |m_extraData| promptly.
+    EAGERLY_FINALIZE();
     DECLARE_TRACE();
 
 private: