Revert of [chromecast] Pass media task runner to MediaPipelineBackendManager.

chromecast/browser/cast_browser_main_parts.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_BROWSER_CAST_BROWSER_MAIN_PARTS_H_
 #define CHROMECAST_BROWSER_CAST_BROWSER_MAIN_PARTS_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/common/main_function_params.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace net {
 class NetLog;
 }
 
 namespace chromecast {
 
 namespace media {
-class MediaPipelineBackendManager;
 class MediaResourceTracker;
 class VideoPlaneController;
 }  // namespace media
 
 namespace shell {
 class CastBrowserProcess;
 class URLRequestContextFactory;
 
 class CastBrowserMainParts : public content::BrowserMainParts {
  public:
   // This class does not take ownership of |url_request_content_factory|.
   CastBrowserMainParts(const content::MainFunctionParams& parameters,
                        URLRequestContextFactory* url_request_context_factory);
   ~CastBrowserMainParts() override;
 
   scoped_refptr<base::SingleThreadTaskRunner> GetMediaTaskRunner() const;
-
 #if !defined(OS_ANDROID)
   media::MediaResourceTracker* media_resource_tracker();
-  media::MediaPipelineBackendManager* media_pipeline_backend_manager();
 #endif
 
   // content::BrowserMainParts implementation:
   void PreMainMessageLoopStart() override;
   void PostMainMessageLoopStart() override;
   void ToolkitInitialized() override;
   int PreCreateThreads() override;
   void PreMainMessageLoopRun() override;
   bool MainMessageLoopRun(int* result_code) override;
   void PostMainMessageLoopRun() override;
   void PostDestroyThreads() override;
 
  private:
   scoped_ptr<CastBrowserProcess> cast_browser_process_;
   const content::MainFunctionParams parameters_;  // For running browser tests.
   URLRequestContextFactory* const url_request_context_factory_;
   scoped_ptr<net::NetLog> net_log_;
   scoped_ptr<media::VideoPlaneController> video_plane_controller_;
 
 #if !defined(OS_ANDROID)
   // Tracks usage of media resource by e.g. CMA pipeline, CDM.
   media::MediaResourceTracker* media_resource_tracker_;
-
-  // Tracks all media pipeline backends.
-  scoped_ptr<media::MediaPipelineBackendManager>
-      media_pipeline_backend_manager_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(CastBrowserMainParts);
 };
 
 }  // namespace shell
 }  // namespace chromecast
 
 #endif  // CHROMECAST_BROWSER_CAST_BROWSER_MAIN_PARTS_H_