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

content/renderer/media/mock_media_stream_dispatcher.cc

Index: content/renderer/media/mock_media_stream_dispatcher.cc
diff --git a/content/renderer/media/mock_media_stream_dispatcher.cc b/content/renderer/media/mock_media_stream_dispatcher.cc
index 5bad676b92529f0c3fd4a57e467cda7a0b90485b..a86f26fa4ef836465671592a14691e21a54a5951 100644
--- a/content/renderer/media/mock_media_stream_dispatcher.cc
+++ b/content/renderer/media/mock_media_stream_dispatcher.cc
@@ -25,19 +25,19 @@ void MockMediaStreamDispatcher::GenerateStream(
   audio_array_.clear();
   video_array_.clear();
 
-  if (components.audio) {
+  if (content::IsAudioMediaStreamDeviceType(components.audio_type)) {
     media_stream::StreamDeviceInfo audio;
-    audio.device_id= "audio_device_id";
-    audio.name ="audio microphone";
-    audio.stream_type = content::MEDIA_STREAM_DEVICE_TYPE_AUDIO_CAPTURE;
+    audio.device_id = "audio_device_id";
+    audio.name = "audio microphone";
+    audio.stream_type = components.audio_type;
     audio.session_id = request_id;
     audio_array_.push_back(audio);
   }
-  if (components.video) {
+  if (content::IsVideoMediaStreamDeviceType(components.video_type)) {
     media_stream::StreamDeviceInfo video;
-    video.device_id= "video_device_id";
-    video.name ="usb video camera";
-    video.stream_type = content::MEDIA_STREAM_DEVICE_TYPE_VIDEO_CAPTURE;
+    video.device_id = "video_device_id";
+    video.name = "usb video camera";
+    video.stream_type = components.video_type;
     video.session_id = request_id;
     video_array_.push_back(video);
   }