Keep auxilliary media objects on the heap always.

Source/modules/mediasource/MediaSource.h

Index: Source/modules/mediasource/MediaSource.h
diff --git a/Source/modules/mediasource/MediaSource.h b/Source/modules/mediasource/MediaSource.h
index 2cc308369506f37e8a4bc97f6bc4c574005bf272..b23a7bc625dfc4d3d2b45ed90fe789ba8c9c4027 100644
--- a/Source/modules/mediasource/MediaSource.h
+++ b/Source/modules/mediasource/MediaSource.h
@@ -79,8 +79,8 @@ public:
     void close() override;
     bool isClosed() const override;
     double duration() const override;
-    PassRefPtrWillBeRawPtr<TimeRanges> buffered() const override;
-    PassRefPtrWillBeRawPtr<TimeRanges> seekable() const override;
+    TimeRanges* buffered() const override;
+    TimeRanges* seekable() const override;
 #if !ENABLE(OILPAN)
     void refHTMLMediaSource() override { ref(); }
     void derefHTMLMediaSource() override { deref(); }