Move direct use of VideoCapturer::VideoAdapter to VideoSinkWants.

webrtc/media/base/videobroadcaster.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 15 matching lines @@
 
   SinkPair* sink_pair = FindSinkPair(sink);
   if (!sink_pair) {
     sinks_.push_back(SinkPair(sink, wants));
   } else {
     sink_pair->wants = wants;
   }
 
   // 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;
   }
 }
 
 void VideoBroadcaster::RemoveSink(
     VideoSinkInterface<cricket::VideoFrame>* sink) {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   RTC_DCHECK(sink != nullptr);
   RTC_DCHECK(FindSinkPair(sink));
 
   sinks_.erase(std::remove_if(sinks_.begin(), sinks_.end(),
                               [sink](const SinkPair& sink_pair) {
                                 return sink_pair.sink == sink;
                               }),
                sinks_.end());
 }
 
 bool VideoBroadcaster::frame_wanted() const {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   return !sinks_.empty();
 }
 
 VideoSinkWants VideoBroadcaster::wants() const {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   return current_wants_;
 }
 
 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);
   }
 }
 
 VideoBroadcaster::SinkPair* VideoBroadcaster::FindSinkPair(
     const VideoSinkInterface<cricket::VideoFrame>* sink) {
   auto sink_pair_it = std::find_if(
       sinks_.begin(), sinks_.end(),
       [sink](const SinkPair& sink_pair) { return sink_pair.sink == sink; });
   if (sink_pair_it != sinks_.end()) {
     return &*sink_pair_it;
   }
   return nullptr;
 }
 
 }  // namespace rtc