Pass camera facing info to audio client

chromeos/audio/cras_audio_handler.h

 // Copyright (c) 2013 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 CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_
 #define CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 #include <queue>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/timer/timer.h"
 #include "chromeos/audio/audio_device.h"
 #include "chromeos/audio/audio_devices_pref_handler.h"
 #include "chromeos/audio/audio_pref_observer.h"
 #include "chromeos/dbus/audio_node.h"
 #include "chromeos/dbus/cras_audio_client.h"
 #include "chromeos/dbus/session_manager_client.h"
 #include "chromeos/dbus/volume_state.h"
 
 namespace chromeos {
 
 class AudioDevicesPrefHandler;
 
+enum class VideoFacingMode {
+  NONE = 0,
+  // Video device is facing the user. I.e. front camera.
+  USER,
+  // Video device is facing the environment. I.e. back camera.
+  ENVIRONMENT
+};
+
+class VideoCaptureObserver {
+ public:
+  virtual void OnVideoCaptureStarted(VideoFacingMode facing) = 0;
+  virtual void OnVideoCaptureStopped(VideoFacingMode facing) = 0;
+};

[jennyz, 2017/02/03 22:44:13]

It is kind of a little weird to define a VideoCaptureObserver in
CrasAudioHandler. Can you put VideorCaptureObserver in the video related file
and use Observer pattern, and use AddObserver/RemoveObserver to either add or
remove CrasAudioHandler object to the Video object that broadcast the video
events?

[shenghao, 2017/02/08 02:07:09]

Talked offline with Jenny. She is trying to find a better place. Otherwise we
will keep it as is.

[jennyz, 2017/02/08 22:21:33]

Have you tried to make a separate target for the media::VideoCaptureObserver
class, instead of building it with //media/base? By making it a separate class,
you can have chromeos depend on this new target, instead of //media/base, then
it breaks the cyclical dependency issue you had before. It will simplify the
code a lot.

[shenghao, 2017/02/09 02:08:51]

Removed this part.

+
 class CHROMEOS_EXPORT CrasAudioHandler : public CrasAudioClient::Observer,
                                          public AudioPrefObserver,
-                                         public SessionManagerClient::Observer {
+                                         public SessionManagerClient::Observer,
+                                         public VideoCaptureObserver {
  public:
-  typedef std::priority_queue<AudioDevice,
-                              std::vector<AudioDevice>,
-                              AudioDeviceCompare> AudioDevicePriorityQueue;
+  typedef std::
+      priority_queue<AudioDevice, std::vector<AudioDevice>, AudioDeviceCompare>
+          AudioDevicePriorityQueue;
   typedef std::vector<uint64_t> NodeIdList;
 
   // Volume change reasons that are not user-initiated.
   enum AutomatedVolumeChangeReason {
     // Indicates it is from initializing audio state.
     VOLUME_CHANGE_INITIALIZING_AUDIO_STATE,
 
     // Indicates it is from restoring volume in maximimize mode screenshot.
     VOLUME_CHANGE_MAXIMIZE_MODE_SCREENSHOT,
   };
@@ skipping 50 matching lines @@
 
   // Destroys the global instance.
   static void Shutdown();
 
   // Returns true if the global instance is initialized.
   static bool IsInitialized();
 
   // Gets the global instance. Initialize must be called first.
   static CrasAudioHandler* Get();
 
+  // Overrides VideoCaptureObserver.
+  void OnVideoCaptureStarted(VideoFacingMode facing) override;
+  void OnVideoCaptureStopped(VideoFacingMode facing) override;
+
   // Adds an audio observer.
   void AddAudioObserver(AudioObserver* observer);
 
   // Removes an audio observer.
   void RemoveAudioObserver(AudioObserver* observer);
 
   // Returns true if keyboard mic exists.
   bool HasKeyboardMic();
 
   // Returns true if audio output is muted for the system.
@@ skipping 362 matching lines @@
   uint64_t init_node_id_;
 
   base::WeakPtrFactory<CrasAudioHandler> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CrasAudioHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_AUDIO_CRAS_AUDIO_HANDLER_H_