[Chromecast] Upgrade to new CMA backend API

chromecast/browser/media/cma_media_pipeline_client.h

 // Copyright 2015 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_BROWSER_MEDIA_CMA_MEDIA_PIPELINE_CLIENT_H_
 #define CHROMECAST_BROWSER_MEDIA_CMA_MEDIA_PIPELINE_CLIENT_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "chromecast/base/cast_resource.h"
 #include "chromecast/public/media/media_pipeline_backend.h"
 
 namespace chromecast {
 namespace media {
 
-// Class to provide media backend and watch media pipeline status
+struct MediaPipelineDeviceParams;
+
+// Class to provide media backend and watch media pipeline status.
 class CmaMediaPipelineClient : public base::RefCounted<CmaMediaPipelineClient>,
                                public CastResource {
  public:
   CmaMediaPipelineClient();
 
   virtual scoped_ptr<MediaPipelineBackend> CreateMediaPipelineBackend(
-      const media::MediaPipelineDeviceParams& params);
+      const MediaPipelineDeviceParams& params);
 
   virtual void OnMediaPipelineBackendCreated();
   virtual void OnMediaPipelineBackendDestroyed();
 
-  // cast::CastResource implementations
+  // cast::CastResource implementation:
   void ReleaseResource(CastResource::Resource resource) override;
 
  protected:
   ~CmaMediaPipelineClient() override;
 
  private:
   friend class base::RefCounted<CmaMediaPipelineClient>;
 
-  // Number of created media pipelines
+  // Number of created media pipelines.
   size_t media_pipeline_count_;
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(CmaMediaPipelineClient);
 };
 }
 }
 
 #endif