[Chromecast] Upgrade to new CMA backend API

chromecast/media/cma/pipeline/video_pipeline.h

-// Copyright 2014 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 CHROMECAST_MEDIA_CMA_PIPELINE_VIDEO_PIPELINE_H_
-#define CHROMECAST_MEDIA_CMA_PIPELINE_VIDEO_PIPELINE_H_
-
-#include "base/macros.h"
-
-namespace chromecast {
-namespace media {
-struct VideoPipelineClient;
-
-class VideoPipeline {
- public:
-  VideoPipeline();
-  virtual ~VideoPipeline();
-
-  virtual void SetClient(const VideoPipelineClient& client) = 0;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(VideoPipeline);
-};
-
-}  // namespace media
-}  // namespace chromecast
-
-#endif  // CHROMECAST_MEDIA_CMA_PIPELINE_VIDEO_PIPELINE_H_