[chromecast] Fix build with enable_mojo_media=true.

chromecast/browser/media/cast_mojo_media_client.h

 // Copyright 2016 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_CAST_MOJO_MEDIA_CLIENT_H_
 #define CHROMECAST_BROWSER_MEDIA_CAST_MOJO_MEDIA_CLIENT_H_
 
+#include "chromecast/browser/media/media_pipeline_backend_factory.h"
 #include "media/mojo/services/mojo_media_client.h"
 
 namespace chromecast {
 namespace media {
 
-class CmaMediaPipelineClient;
-
 class CastMojoMediaClient : public ::media::MojoMediaClient {
  public:
-  CastMojoMediaClient(scoped_refptr<CmaMediaPipelineClient> pipeline_client);
+  CastMojoMediaClient(const CreateMediaPipelineBackendCB& create_backend_cb);
   ~CastMojoMediaClient() override;
 
   // MojoMediaClient overrides.
   scoped_ptr<::media::RendererFactory> CreateRendererFactory(
       const scoped_refptr<::media::MediaLog>& media_log) override;
 
  private:
-  scoped_refptr<CmaMediaPipelineClient> pipeline_client_;
+  const CreateMediaPipelineBackendCB create_backend_cb_;
   DISALLOW_COPY_AND_ASSIGN(CastMojoMediaClient);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_BROWSER_MEDIA_CAST_MOJO_MEDIA_CLIENT_H_