Add framerate to VideoSinkWants and ability to signal on overuse

webrtc/media/base/videoadapter.h

Index: webrtc/media/base/videoadapter.h
diff --git a/webrtc/media/base/videoadapter.h b/webrtc/media/base/videoadapter.h
index caaab3ce6c144f75737db3eea6471c22f0c4e5f3..f1d28f705988562621e76552d270a8084de46764 100644
--- a/webrtc/media/base/videoadapter.h
+++ b/webrtc/media/base/videoadapter.h
@@ -25,7 +25,9 @@ namespace cricket {
 class VideoAdapter {
  public:
   VideoAdapter();
-  VideoAdapter(int required_resolution_alignment);
+  // The output frames will have height and width that is divisible by
+  // |required_resolution_alignment|.
+  explicit VideoAdapter(int required_resolution_alignment);
   virtual ~VideoAdapter();
 
   // Return the adapted resolution and cropping parameters given the
@@ -53,8 +55,12 @@ class VideoAdapter {
   // pixels. If |target_pixel_count| is not set, treat it as being equal to
   // |max_pixel_count|. If |max_pixel_count| is not set, treat is as being the
   // highest resolution available.
-  void OnResolutionRequest(const rtc::Optional<int>& target_pixel_count,
-                           const rtc::Optional<int>& max_pixel_count);
+  // |framerate_fps| is essentially analogous to |max_pixel_count|, but for
+  // framerate rather than resolution.
+  void OnResolutionFramerateRequest(
+      const rtc::Optional<int>& target_pixel_count,
+      const rtc::Optional<int>& max_pixel_count,
+      const rtc::Optional<int>& framerate_fps);
 
  private:
   // Determine if frame should be dropped based on input fps and requested fps.
@@ -77,6 +83,7 @@ class VideoAdapter {
   rtc::Optional<VideoFormat> requested_format_ GUARDED_BY(critical_section_);
   int resolution_request_target_pixel_count_ GUARDED_BY(critical_section_);
   int resolution_request_max_pixel_count_ GUARDED_BY(critical_section_);
+  int max_framerate_request_ GUARDED_BY(critical_section_);
 
   // The critical section to protect the above variables.
   rtc::CriticalSection critical_section_;