Add VideoTrackSink interface to content/public

content/public/renderer/media_stream_sink.h

Index: content/public/renderer/media_stream_sink.h
diff --git a/content/public/renderer/media_stream_sink.h b/content/public/renderer/media_stream_sink.h
new file mode 100644
index 0000000000000000000000000000000000000000..d910e9c7e69a51b24a4607aa3944add9896f6187
--- /dev/null
+++ b/content/public/renderer/media_stream_sink.h
@@ -0,0 +1,25 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_SINK_H_
+#define CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_SINK_H_
+
+#include "base/compiler_specific.h"
+#include "content/common/content_export.h"
+#include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
+
+namespace content {
+
+class CONTENT_EXPORT MediaStreamSink {
+ public:
+  virtual void OnReadyStateChanged(
+      blink::WebMediaStreamSource::ReadyState state) {}
+
+ protected:
+  virtual ~MediaStreamSink() {}
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_SINK_H_