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

content/common/media/media_stream_options.h

Index: content/common/media/media_stream_options.h
diff --git a/content/common/media/media_stream_options.h b/content/common/media/media_stream_options.h
index c51d700ee8b5a68088d444f6b429a23ec6c9e80d..2dc3877cb166d7b2b1fe343e904226c7b3d486e4 100644
--- a/content/common/media/media_stream_options.h
+++ b/content/common/media/media_stream_options.h
@@ -13,22 +13,28 @@
 
 namespace media_stream {
 
+typedef content::MediaStreamDeviceType MediaStreamType;
+
 // StreamOptions is a Chromium representation of WebKit's
 // WebUserMediaRequest Options. It describes the components
 // in a request for a new media stream.
 struct CONTENT_EXPORT StreamOptions {
-  StreamOptions() : audio(false), video(false) {}
-  StreamOptions(bool audio, bool video)
-      : audio(audio), video(video) {}
+  StreamOptions();
+  // TODO(miu): Remove the 2-bools ctor in later clean-up CL.
+  StreamOptions(bool user_audio, bool user_video);
+  StreamOptions(MediaStreamType audio_type, MediaStreamType video_type,
+                const std::string& opt_device_id);
 
-  // True if the stream shall contain an audio input stream.
-  bool audio;
+  // If not NO_SERVICE, the stream shall contain an audio input stream.
+  MediaStreamType audio_type;
 
-  // True if the stream shall contain a video input stream.
-  bool video;
-};
+  // If not NO_SERVICE, the stream shall contain a video input stream.
+  MediaStreamType video_type;
 
-typedef content::MediaStreamDeviceType MediaStreamType;
+  // If empty, user is allowed to choose from among all available devices.
+  // Otherwise, this selects a specific device.
+  std::string opt_device_id;
+};
 
 // StreamDeviceInfo describes information about a device.
 struct CONTENT_EXPORT StreamDeviceInfo {