Add histogram for percentage of sent frames that are limited in resolution due to bandwidth.

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 60d962f93b3a1cdf541868fab929001fdce7d801..1a5a779a1578950700c183b09e3e2daff2fbccc8 100644
--- a/webrtc/video/send_statistics_proxy.h
+++ b/webrtc/video/send_statistics_proxy.h
@@ -93,8 +93,10 @@ class SendStatisticsProxy : public CpuOveruseMetricsObserver,
                             uint32_t ssrc) override;
 
  private:
-  struct SampleCounter {
+  class SampleCounter {
+   public:
     SampleCounter() : sum(0), num_samples(0) {}
+    ~SampleCounter() {}
     void Add(int sample);
     int Avg(int min_required_samples) const;
 
@@ -102,6 +104,17 @@ class SendStatisticsProxy : public CpuOveruseMetricsObserver,
     int sum;
     int num_samples;
   };
+  class BoolSampleCounter {
+   public:
+    BoolSampleCounter() : sum(0), num_samples(0) {}
+    ~BoolSampleCounter() {}
+    void Add(bool sample);
+    int Percent(int min_required_samples) const;
+
+   private:
+    int sum;
+    int num_samples;
+  };
   struct StatsUpdateTimes {
     StatsUpdateTimes() : resolution_update_ms(0) {}
     int64_t resolution_update_ms;
@@ -129,6 +142,8 @@ class SendStatisticsProxy : public CpuOveruseMetricsObserver,
   SampleCounter sent_width_counter_ GUARDED_BY(crit_);
   SampleCounter sent_height_counter_ GUARDED_BY(crit_);
   SampleCounter encode_time_counter_ GUARDED_BY(crit_);
+  BoolSampleCounter bw_limited_frame_counter_ GUARDED_BY(crit_);
+  SampleCounter bw_resolutions_disabled_counter_ GUARDED_BY(crit_);
 };
 
 }  // namespace webrtc