Begin adding support for tab mirroring via the MediaStream audio/video capturing

content/browser/renderer_host/media/media_stream_manager.h

Index: content/browser/renderer_host/media/media_stream_manager.h
diff --git a/content/browser/renderer_host/media/media_stream_manager.h b/content/browser/renderer_host/media/media_stream_manager.h
index bb407cea0a373851c4a85a058f1fdd5b3730a0a1..aef6f7d79ffdc338f25c3f4695c2c08e88cd5b10 100644
--- a/content/browser/renderer_host/media/media_stream_manager.h
+++ b/content/browser/renderer_host/media/media_stream_manager.h
@@ -24,7 +24,6 @@
 
 #include <map>
 #include <string>
-#include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
@@ -44,6 +43,10 @@ class ScopedCOMInitializer;
 }
 }
 
+namespace media {
+class AudioManager;
+}
+
 namespace media_stream {
 
 class AudioInputDeviceManager;
@@ -76,24 +79,21 @@ class CONTENT_EXPORT MediaStreamManager
       public SettingsRequester,
       public base::SystemMonitor::DevicesChangedObserver {
  public:
-  // This class takes the ownerships of the |audio_input_device_manager|
-  // and |video_capture_manager|.
-  MediaStreamManager(AudioInputDeviceManager* audio_input_device_manager,
-                     VideoCaptureManager* video_capture_manager);
-
+  MediaStreamManager();
   virtual ~MediaStreamManager();
 
-  // Used to access VideoCaptureManager.
-  VideoCaptureManager* video_capture_manager();
+  // Used to access the VideoCaptureManager for the given |stream_type|.
+  VideoCaptureManager* GetVideoCaptureManager(MediaStreamType stream_type);
 
-  // Used to access AudioInputDeviceManager.
-  AudioInputDeviceManager* audio_input_device_manager();
+  // Used to access the AudioInputDeviceManager for the given |stream_type|.
+  AudioInputDeviceManager* GetAudioInputDeviceManager(
+      MediaStreamType stream_type);
 
   // GenerateStream opens new media devices according to |components|. It
   // creates a new request which is identified by a unique |label| that's
   // returned to the caller.
   void GenerateStream(MediaStreamRequester* requester, int render_process_id,
-                      int render_view_id, const StreamOptions& options,
+                      int render_view_id, const StreamOptions& components,
                       const GURL& security_origin, std::string* label);
 
   // Cancel generate stream.
@@ -146,6 +146,11 @@ class CONTENT_EXPORT MediaStreamManager
   virtual void OnDevicesChanged(
       base::SystemMonitor::DeviceType device_type) OVERRIDE;
 
+  // Used by unit tests to provide an alternate AudioManager instance.
+  // Normally, BrowserMainLoop::GetAudioManager() is used to gain access to the
+  // AudioManager.

[no longer working on chromium, 2012/08/31 13:38:23]

Add a comment to specify that this function needs to be called before accessing
audio device manager.

[miu, 2012/09/01 01:32:00]

Done.

+  void UseAudioManager(media::AudioManager* audio_manager);

[no longer working on chromium, 2012/08/31 13:38:23]

nit, SetAudioManager?

[miu, 2012/09/01 01:32:00]

Done.

+
   // Used by unit test to make sure fake devices are used instead of a real
   // devices, which is needed for server based testing.
   // TODO(xians): Remove this hack since we can create our own
@@ -187,9 +192,10 @@ class CONTENT_EXPORT MediaStreamManager
   bool HasEnumerationRequest();
   void ClearEnumerationCache(EnumerationCache* cache);
 
-  // Helper to ensure the device thread and pass the message loop to device
-  // managers, it also register itself as the listener to the device managers.
-  void EnsureDeviceThreadAndListener();
+  // Helper to create the device manager for the given stream_type, if needed.
+  // Auto-starts the device thread and registers this as a listener with the
+  // device managers.
+  void EnsureDeviceManagerStarted(MediaStreamType stream_type);
 
   // Sends cached device list to a client corresponding to the request
   // identified by |label|.
@@ -206,16 +212,20 @@ class CONTENT_EXPORT MediaStreamManager
   scoped_ptr<base::Thread> device_thread_;
 
   scoped_ptr<MediaStreamDeviceSettings> device_settings_;
-  scoped_refptr<AudioInputDeviceManager> audio_input_device_manager_;
-  scoped_refptr<VideoCaptureManager> video_capture_manager_;
+
+  media::AudioManager* audio_manager_;  // not owned
+
+  // Device managers, instantiated on-demand.
+  scoped_refptr<MediaStreamProvider> device_manager_[
+      content::NUM_MEDIA_STREAM_DEVICE_TYPES];
 
   // Indicator of device monitoring state.
   bool monitoring_started_;
 
   // Stores most recently enumerated device lists. The cache is cleared when
   // monitoring is stopped or there is no request for that type of device.
-  EnumerationCache audio_enumeration_cache_;
-  EnumerationCache video_enumeration_cache_;
+  EnumerationCache user_audio_enumeration_cache_;
+  EnumerationCache user_video_enumeration_cache_;
 
   // Keeps track of live enumeration commands sent to VideoCaptureManager or
   // AudioInputDeviceManager, in order to only enumerate when necessary.