Reland of Add framerate to VideoSinkWants and ability to signal on overuse

webrtc/video/send_statistics_proxy.h

Index: webrtc/video/send_statistics_proxy.h
diff --git a/webrtc/video/send_statistics_proxy.h b/webrtc/video/send_statistics_proxy.h
index 37db3b0a09307f9a0d8d825fb7d13ca9988fbea0..52609498d57239bd3536e1b908b992521dc73d2f 100644
--- a/webrtc/video/send_statistics_proxy.h
+++ b/webrtc/video/send_statistics_proxy.h
@@ -50,7 +50,7 @@ class SendStatisticsProxy : public CpuOveruseMetricsObserver,
                       VideoEncoderConfig::ContentType content_type);
   virtual ~SendStatisticsProxy();
 
-  VideoSendStream::Stats GetStats();
+  virtual VideoSendStream::Stats GetStats();
 
   virtual void OnSendEncodedImage(const EncodedImage& encoded_image,
                                   const CodecSpecificInfo* codec_info);
@@ -212,6 +212,7 @@ class SendStatisticsProxy : public CpuOveruseMetricsObserver,
     TargetRateUpdates target_rate_updates_;
     ReportBlockStats report_block_stats_;
     const VideoSendStream::Stats start_stats_;
+
     std::map<int, QpCounters>
         qp_counters_;  // QP counters mapped by spatial idx.
   };