MediaSource must use ref-counting to handle pending activity counting.

Source/core/html/HTMLMediaSource.h

Index: Source/core/html/HTMLMediaSource.h
diff --git a/Source/core/html/HTMLMediaSource.h b/Source/core/html/HTMLMediaSource.h
index 14baccb8e498df6f84c8592f6cf0b0da38bbf90b..eaf5883d8e58fe77611b8b3651c761bb9a43e524 100644
--- a/Source/core/html/HTMLMediaSource.h
+++ b/Source/core/html/HTMLMediaSource.h
@@ -32,6 +32,7 @@
 #define HTMLMediaSource_h
 
 #include "core/html/URLRegistry.h"
+#include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
 
 namespace blink {
@@ -43,13 +44,15 @@ namespace WebCore {
 class HTMLMediaElement;
 class TimeRanges;
 
-class HTMLMediaSource : public URLRegistrable {
+class HTMLMediaSource : public URLRegistrable, public WillBeGarbageCollectedMixin {
 public:
     static void setRegistry(URLRegistry*);
     static HTMLMediaSource* lookup(const String& url) { return s_registry ? static_cast<HTMLMediaSource*>(s_registry->lookup(url)) : 0; }
 
+#if !ENABLE(OILPAN)
     void ref() { refHTMLMediaSource(); }
     void deref() { derefHTMLMediaSource(); }
+#endif
 
     // Called when an HTMLMediaElement is attempting to attach to this object,
     // and helps enforce attachment to at most one element at a time.
@@ -64,12 +67,16 @@ public:
     virtual bool isClosed() const = 0;
     virtual double duration() const = 0;
     virtual PassRefPtr<TimeRanges> buffered() const = 0;
+#if !ENABLE(OILPAN)
     virtual void refHTMLMediaSource() = 0;
     virtual void derefHTMLMediaSource() = 0;
+#endif
 
     // URLRegistrable
     virtual URLRegistry& registry() const OVERRIDE { return *s_registry; }
 
+    virtual void trace(Visitor*) { }
+
 private:
     static URLRegistry* s_registry;
 };