Add qp counter for H264 in SendStatisticsProxy.

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 89c40659b5959ed080d005c531ae725f4e3e08ac..ec2fe4c50e93c2be31496e61030b9ade246df839 100644
--- a/webrtc/video/send_statistics_proxy.h
+++ b/webrtc/video/send_statistics_proxy.h
@@ -138,8 +138,9 @@ class SendStatisticsProxy : public CpuOveruseMetricsObserver,
     int64_t bitrate_update_ms;
   };
   struct QpCounters {
-    SampleCounter vp8;  // QP range: 0-127
-    SampleCounter vp9;  // QP range: 0-255
+    SampleCounter vp8;   // QP range: 0-127
+    SampleCounter vp9;   // QP range: 0-255
+    SampleCounter h264;  // QP range: 0-51
   };
   void PurgeOldStats() EXCLUSIVE_LOCKS_REQUIRED(crit_);
   VideoSendStream::StreamStats* GetStatsEntry(uint32_t ssrc)