Extend content::DesktopMediaID to allow Aura windows as capture sources.

content/renderer/media/media_stream_impl.cc

Index: content/renderer/media/media_stream_impl.cc
diff --git a/content/renderer/media/media_stream_impl.cc b/content/renderer/media/media_stream_impl.cc
index 1deb444221c2c7429f1ab6fcc415db29946e4f0a..b96625ba0adacc681fe725e921bef43dd2b94533 100644
--- a/content/renderer/media/media_stream_impl.cc
+++ b/content/renderer/media/media_stream_impl.cc
@@ -10,7 +10,6 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
-#include "content/public/common/desktop_media_id.h"
 #include "content/renderer/media/media_stream_audio_renderer.h"
 #include "content/renderer/media/media_stream_dependency_factory.h"
 #include "content/renderer/media/media_stream_dispatcher.h"
@@ -74,8 +73,8 @@ void UpdateRequestOptions(
           kMediaStreamSourceId, true);
     } else if (video_stream_source == kMediaStreamSourceScreen) {
       options->video_type = content::MEDIA_DESKTOP_VIDEO_CAPTURE;
-      options->video_device_id =
-          DesktopMediaID(DesktopMediaID::TYPE_SCREEN, 0).ToString();
+      // Set empty video device ID when screen capture is requested.
+      options->video_device_id.clear();
     } else if (video_stream_source == kMediaStreamSourceDesktop) {
       options->video_type = content::MEDIA_DESKTOP_VIDEO_CAPTURE;
       options->video_device_id = GetStreamConstraint(