Pass camera facing info to audio client

components/arc/video_facing.h

+// Copyright 2016 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 COMPONENTS_ARC_VIDEO_FACING_H_
+#define COMPONENTS_ARC_VIDEO_FACING_H_
+
+namespace component {
+
+enum VideoFacingMode {

[chfremer, 2017/01/20 18:23:52]

Can we make this an enum class?

[shenghao, 2017/01/24 12:52:00]

Done.

+  NONE = 0,

[chfremer, 2017/01/20 18:23:52]

Why is this entry needed and what does it mean?

[shenghao, 2017/01/24 12:52:00]

This enum should have 1-1 mapping from VideoFacingMode in
//media/base/video_facing.h.
The "NONE" here is useful for some devices that do not have facing, such as
desktop capturing.

+  // Video device is facing the user. I.e. front camera.
+  USER,
+  // Video device is facing the environment. I.e. back camera.
+  ENVIRONMENT
+};

[chfremer, 2017/01/20 18:23:52]

Thinking about convertible devices, could it happen that the notion of which
camera faces the user changes when the device is "converted", e.g. flipped over?
If so, should we revise the enum value names?

[shenghao, 2017/01/24 12:52:00]

Yeah I am aware of the convertibles. However I still want to name it
"environment-facing" cameras even though it can flip to the same side as
"user-facing" cameras. The audio devices are mounted at similar positions as
cameras, so when environment-facing camera is active, the environment-facing
audio device should be active, whether the camera is flipped is unrelated.

+
+class VideoCaptureObserver {
+ public:
+  virtual void OnVideoCaptureStarted(VideoFacingMode facing) = 0;
+  virtual void OnVideoCaptureStopped(VideoFacingMode facing) = 0;
+};
+
+}
+
+#endif  // COMPONENTS_ARC_VIDEO_FACING_H_
+