Reland of Drop frames until specified bitrate is achieved.

webrtc/api/video/video_frame.h

Index: webrtc/api/video/video_frame.h
diff --git a/webrtc/api/video/video_frame.h b/webrtc/api/video/video_frame.h
index 5c57213f018aabbf28549d3a66031a3111778822..8840782cad03ba70e69657b227e8ddf7aabfbcb3 100644
--- a/webrtc/api/video/video_frame.h
+++ b/webrtc/api/video/video_frame.h
@@ -48,9 +48,10 @@ class VideoFrame {
 
   // Get frame width.
   int width() const;
-
   // Get frame height.
   int height() const;
+  // Get frame size in pixels.
+  uint32_t size() const;
 
   // System monotonic clock, same timebase as rtc::TimeMicros().
   int64_t timestamp_us() const { return timestamp_us_; }