Move the device enumerate/open/close work to device thread from IO thread

content/browser/renderer_host/media/media_stream_dispatcher_host.h

 // Copyright (c) 2012 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 CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_DISPATCHER_HOST_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_DISPATCHER_HOST_H_
 
 #include <map>
 #include <string>
 #include <utility>
 
 #include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "content/browser/renderer_host/media/media_stream_requester.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
 #include "content/public/browser/browser_message_filter.h"
 
-namespace content {
-class ResourceContext;
-}  // namespace content
-
 namespace media_stream {
 
 // MediaStreamDispatcherHost is a delegate for Media Stream API messages used by
 // MediaStreamImpl. It's the complement of MediaStreamDispatcher
 // (owned by RenderView).
 class CONTENT_EXPORT MediaStreamDispatcherHost
     : public content::BrowserMessageFilter,
       public MediaStreamRequester {
  public:
-  MediaStreamDispatcherHost(content::ResourceContext* resource_context,
-                            int render_process_id,
-                            media::AudioManager* audio_manager);
+  explicit MediaStreamDispatcherHost(int render_process_id);
 
   // MediaStreamRequester implementation.
   virtual void StreamGenerated(
       const std::string& label,
       const StreamDeviceInfoArray& audio_devices,
       const StreamDeviceInfoArray& video_devices) OVERRIDE;
   virtual void StreamGenerationFailed(const std::string& label) OVERRIDE;
   virtual void AudioDeviceFailed(const std::string& label, int index) OVERRIDE;
   virtual void VideoDeviceFailed(const std::string& label, int index) OVERRIDE;
   virtual void DevicesEnumerated(const std::string& label,
@@ skipping 27 matching lines @@
                           media_stream::MediaStreamType type,
                           const GURL& security_origin);
 
   void OnOpenDevice(int render_view_id,
                     int page_request_id,
                     const std::string& device_id,
                     media_stream::MediaStreamType type,
                     const GURL& security_origin);
 
   // Returns the media stream manager to forward events to,
-  // creating one if needed.
-  MediaStreamManager* manager();
+  // creating one if needed. It is a virtual function so that the unit tests
+  // can inject their own MediaStreamManager.
+  virtual MediaStreamManager* GetManager();
 
-  content::ResourceContext* resource_context_;
   int render_process_id_;
-  media::AudioManager* audio_manager_;
 
   struct StreamRequest;
   typedef std::map<std::string, StreamRequest> StreamMap;
   // Streams generated for this host.
   StreamMap streams_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaStreamDispatcherHost);
 };
 
 }  // namespace media_stream
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_MEDIA_STREAM_DISPATCHER_HOST_H_