[Chromecast] Cleanup the API for creating MediaPipelineBackend.

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 media {
-class AudioManagerFactory;
-}
-
 namespace net {
 class NetLog;
 }
 
 namespace chromecast {
 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,
-      scoped_ptr<::media::AudioManagerFactory> audio_manager_factory);
+  CastBrowserMainParts(const content::MainFunctionParams& parameters,
+                       URLRequestContextFactory* url_request_context_factory);
   ~CastBrowserMainParts() override;
 
   // content::BrowserMainParts implementation:
   void PreMainMessageLoopStart() override;
   void PostMainMessageLoopStart() override;
   int PreCreateThreads() override;
   void PreMainMessageLoopRun() override;
   bool MainMessageLoopRun(int* result_code) override;
   void PostMainMessageLoopRun() override;
 
  private:
   scoped_ptr<CastBrowserProcess> cast_browser_process_;
   const content::MainFunctionParams parameters_;  // For running browser tests.
   URLRequestContextFactory* const url_request_context_factory_;
-  scoped_ptr<::media::AudioManagerFactory> audio_manager_factory_;
   scoped_ptr<net::NetLog> net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(CastBrowserMainParts);
 };
 
 }  // namespace shell
 }  // namespace chromecast
 
 #endif  // CHROMECAST_BROWSER_CAST_BROWSER_MAIN_PARTS_H_