Pass camera facing info to audio client

content/browser/renderer_host/media/video_capture_manager.h

Index: content/browser/renderer_host/media/video_capture_manager.h
diff --git a/content/browser/renderer_host/media/video_capture_manager.h b/content/browser/renderer_host/media/video_capture_manager.h
index 2136b308d02a6ca0e060aea10b3a123f6d6af1c3..9304b71fff4c54f39ebc90a30d0ce90b618084f3 100644
--- a/content/browser/renderer_host/media/video_capture_manager.h
+++ b/content/browser/renderer_host/media/video_capture_manager.h
@@ -29,6 +29,7 @@
 #include "content/browser/renderer_host/media/video_capture_controller_event_handler.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
+#include "media/base/video_facing.h"
 #include "media/capture/video/video_capture_device.h"
 #include "media/capture/video/video_capture_device_factory.h"
 #include "media/capture/video_capture_types.h"
@@ -53,6 +54,16 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   explicit VideoCaptureManager(
       std::unique_ptr<media::VideoCaptureDeviceFactory> factory);
 
+  // AddVideoCaptureObserver() can be called only before any devices are opened.
+  // RemoveAllVideoCaptureObservers() can be called only after all devices
+  // are closed.
+  // They can be called more than once and it's ok to not call at all if the
+  // client is not interested in receiving media::VideoCaptureObserver callacks.
+  // This methods can be called on whatever thread. The callbacks of
+  // media::VideoCaptureObserver arrive on browser IO thread.
+  void AddVideoCaptureObserver(media::VideoCaptureObserver* observer);
+  void RemoveAllVideoCaptureObservers();
+
   void Unregister();
 
   // Implements MediaStreamProvider.
@@ -336,6 +347,8 @@ class CONTENT_EXPORT VideoCaptureManager : public MediaStreamProvider {
   std::unique_ptr<media::VideoCaptureDeviceFactory>
       video_capture_device_factory_;
 
+  std::vector<media::VideoCaptureObserver*> capture_observers_;

[jennyz, 2017/02/10 18:28:28]

Why don't use base::ObserverList<media::VideoCaptureObserver>, then you can use
.AddObserver, RemoveObserver, etc, to manage the observers.
see https://cs.chromium.org/chromium/src/base/observer_list.h

[shenghao, 2017/02/11 00:54:51]

Done.

+
   // Local cache of the enumerated video capture devices' names and capture
   // supported formats. A snapshot of the current devices and their capabilities
   // is composed in VideoCaptureDeviceFactory::EnumerateDeviceNames() and