Add WebKit prefix to MediaSource,SourceBuffer, and SourceBufferList objects.

Source/core/platform/graphics/MediaPlayerPrivate.h

Index: Source/core/platform/graphics/MediaPlayerPrivate.h
diff --git a/Source/core/platform/graphics/MediaPlayerPrivate.h b/Source/core/platform/graphics/MediaPlayerPrivate.h
index 4afdc1b5854979b3624fad67d18eaed54ac4b64f..99954e6ef462f2e6aa9396d3c07620f19c9e911d 100644
--- a/Source/core/platform/graphics/MediaPlayerPrivate.h
+++ b/Source/core/platform/graphics/MediaPlayerPrivate.h
@@ -43,7 +43,7 @@ public:
     virtual ~MediaPlayerPrivateInterface() { }
 
     virtual void load(const String& url) = 0;
-    virtual void load(const String& url, PassRefPtr<MediaSource>) = 0;
+    virtual void load(const String& url, PassRefPtr<WebKitMediaSource>) = 0;
     virtual void cancelLoad() = 0;
 
     virtual void prepareToPlay() { }