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..157abbc372051f334704d3f9121c1aa1856bbebe 100644
--- a/webrtc/media/base/videobroadcaster.cc
+++ b/webrtc/media/base/videobroadcaster.cc
@@ -33,8 +33,43 @@ void VideoBroadcaster::AddOrUpdateSink(
 
   // Rotation must be applied by the source if one sink wants it.
   current_wants_.rotation_applied = false;
+  current_wants_.resolution =
+      rtc::Optional<VideoSinkWants::ResolutionRequest>();
+  rtc::Optional<VideoSinkWants::ResolutionRequest> resolution;
+  bool sink_agrees_on_resolution = true;

[pthatcher1, 2016/02/19 06:08:40]

I think you mean sinks_agree_on_resolution

   for (auto& sink_pair : sinks_) {
     current_wants_.rotation_applied |= sink_pair.wants.rotation_applied;
+
+    if (sink_agrees_on_resolution && sink_pair.wants.resolution) {
+      if (sink_pair.wants.resolution->request ==
+              VideoSinkWants::ResolutionRequest::kLargerThan &&
+          sink_pair.wants.resolution->seen_number_of_pixels <
+              current_number_of_pixels_) {

[pthatcher1, 2016/02/19 06:08:40]

This would be more clear reversed as "if (current > wants)" than "if (wants <
current)".

+        continue;
+      }
+
+      if (sink_pair.wants.resolution->request ==
+              VideoSinkWants::ResolutionRequest::kSmallerThan &&
+          sink_pair.wants.resolution->seen_number_of_pixels >
+              current_number_of_pixels_) {

[pthatcher1, 2016/02/19 06:08:40]

Same here: "if (wants < current)" would be more clear than "if (current >
wants)".

+        continue;
+      }
+
+      if (!resolution) {
+        resolution = sink_pair.wants.resolution;
+        continue;
+      }
+
+      if (*resolution != *sink_pair.wants.resolution) {
+        sink_agrees_on_resolution = false;
+      }
+    }
+  }
+
+  // If all sinks agree, the source should try to fulfill the resolution
+  // request.
+  if (sink_agrees_on_resolution) {
+    current_wants_.resolution = resolution;
   }
 }
 
@@ -63,6 +98,7 @@ VideoSinkWants VideoBroadcaster::wants() const {
 
 void VideoBroadcaster::OnFrame(const cricket::VideoFrame& frame) {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
+  current_number_of_pixels_ = frame.GetWidth() * frame.GetHeight();

[pthatcher1, 2016/02/19 06:08:40]

I think it would be better to save this as last_frame_pixel_count_

[pthatcher1, 2016/02/19 06:08:40]

Since the pixel count may have changed, I think you have to re-calculate  the
current_wants_.

   for (auto& sink_pair : sinks_) {
     sink_pair.sink->OnFrame(frame);
   }