Oilpan: move the MediaPlayer and MediaPlayerClient objects to the heap.

Source/platform/heap/Handle.h

Index: Source/platform/heap/Handle.h
diff --git a/Source/platform/heap/Handle.h b/Source/platform/heap/Handle.h
index 6a46cef73a1b9bbf1ee303b986977ceb9d7d81f2..5c2f8899de67194b8f8c5e3349ec1d899c69b6f1 100644
--- a/Source/platform/heap/Handle.h
+++ b/Source/platform/heap/Handle.h
@@ -877,6 +877,10 @@ public:
     ~DummyBase() { }
 };
 
+// Export this instance to support WillBeGarbageCollectedMixin
+// uses by code residing in non-webcore components.
+template class PLATFORM_EXPORT DummyBase<void>;
+
 #define PassRefPtrWillBeRawPtr WTF::PassRefPtr
 #define RefCountedWillBeGarbageCollected WTF::RefCounted
 #define RefCountedWillBeGarbageCollectedFinalized WTF::RefCounted