Move direct use of VideoCapturer::VideoAdapter to VideoSinkWants.

webrtc/media/base/videobroadcaster.cc

Index: webrtc/media/base/videobroadcaster.cc
diff --git a/webrtc/media/base/videobroadcaster.cc b/webrtc/media/base/videobroadcaster.cc
index e369ee07c632480404080415271572d593c87f06..d45a89dafce6ce5316717a6c68f5bccb0be0abd7 100644
--- a/webrtc/media/base/videobroadcaster.cc
+++ b/webrtc/media/base/videobroadcaster.cc
@@ -36,6 +36,11 @@ void VideoBroadcaster::AddOrUpdateSink(
   for (auto& sink_pair : sinks_) {
     current_wants_.rotation_applied |= sink_pair.wants.rotation_applied;
   }
+
+  // Only store the last request for scaling up / down...
+  // TODO(perkj): This would be simpler if the resolution request was for a
+  // fixed resolution.
+  current_wants_.resolution = wants.resolution;
 }
 
 void VideoBroadcaster::RemoveSink(