MediaStreamVideoSource exports current video format

content/public/renderer/media_stream_api.h

 // Copyright 2015 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_PUBLIC_RENDERER_MEDIA_STREAM_API_H_
 #define CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_API_H_
 
 #include "content/common/content_export.h"
 #include "media/base/audio_capturer_source.h"
 #include "media/base/channel_layout.h"
+#include "media/base/video_capture_types.h"
 #include "media/base/video_capturer_source.h"
 
 namespace blink {
 class WebMediaStream;
+class WebMediaStreamTrack;
 }
 
 namespace content {
 // These methods create a WebMediaStreamSource + MediaStreamSource pair with the
 // provided audio or video capturer source. A new WebMediaStreamTrack +
 // MediaStreamTrack pair is created, connected to the source and is plugged into
 // the WebMediaStream (|web_media_stream|).
 // |is_remote| should be true if the source of the data is not a local device.
 // |is_readonly| should be true if the format of the data cannot be changed by
 //     MediaTrackConstraints.
 CONTENT_EXPORT bool AddVideoTrackToMediaStream(
     scoped_ptr<media::VideoCapturerSource> video_source,
     bool is_remote,
     bool is_readonly,
     blink::WebMediaStream* web_media_stream);
 
 // |sample_rate|, |channel_layout|, and |frames_per_buffer| specify the audio
 // parameters of the track. Generally, these should match the |audio_source| so
 // that it does not have to perform unnecessary sample rate conversion or
 // channel mixing.
 CONTENT_EXPORT bool AddAudioTrackToMediaStream(
     scoped_refptr<media::AudioCapturerSource> audio_source,
     int sample_rate,
     media::ChannelLayout channel_layout,
     int frames_per_buffer,
     bool is_remote,
     bool is_readonly,
     blink::WebMediaStream* web_media_stream);
 
+// On success returns pointer to the current format of the given video track;
+// returns nullptr on failure (if the argument is invalid or if the format
+// cannot be retrieved at the moment).
+CONTENT_EXPORT const media::VideoCaptureFormat* GetCurrentVideoTrackFormat(
+    const blink::WebMediaStreamTrack& video_track);
+
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_API_H_