Piggybacking simulcast id and ALR experiment id into video content type extension.

webrtc/video/receive_statistics_proxy.h

Index: webrtc/video/receive_statistics_proxy.h
diff --git a/webrtc/video/receive_statistics_proxy.h b/webrtc/video/receive_statistics_proxy.h
index 8aff1a254c47ec6c79f50696cb13009350822d98..b0732533bd4d1b8e26430e5ba95ae4c85605604a 100644
--- a/webrtc/video/receive_statistics_proxy.h
+++ b/webrtc/video/receive_statistics_proxy.h
@@ -18,6 +18,7 @@
 #include "webrtc/common_video/include/frame_callback.h"
 #include "webrtc/modules/video_coding/include/video_coding_defines.h"
 #include "webrtc/rtc_base/criticalsection.h"
+#include "webrtc/rtc_base/optional.h"
 #include "webrtc/rtc_base/rate_statistics.h"
 #include "webrtc/rtc_base/ratetracker.h"
 #include "webrtc/rtc_base/thread_annotations.h"
@@ -94,16 +95,23 @@ class ReceiveStatisticsProxy : public VCMReceiveStatisticsCallback,
     SampleCounter() : sum(0), num_samples(0) {}
     void Add(int sample);
     int Avg(int64_t min_required_samples) const;
+    int Max() const;
     void Reset();
 
    private:
     int64_t sum;
     int64_t num_samples;
+    rtc::Optional<int64_t> max;
   };
   struct QpCounters {
     SampleCounter vp8;
   };
 
+  struct ContentSpecificStats {
+    SampleCounter e2e_delay_counter;
+    SampleCounter interframe_delay_counter;
+  };
+
   void UpdateHistograms() EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
   void QualitySample() EXCLUSIVE_LOCKS_REQUIRED(crit_);
@@ -144,14 +152,8 @@ class ReceiveStatisticsProxy : public VCMReceiveStatisticsCallback,
   SampleCounter target_delay_counter_ GUARDED_BY(crit_);
   SampleCounter current_delay_counter_ GUARDED_BY(crit_);
   SampleCounter delay_counter_ GUARDED_BY(crit_);
-  SampleCounter e2e_delay_counter_video_ GUARDED_BY(crit_);
-  SampleCounter e2e_delay_counter_screenshare_ GUARDED_BY(crit_);
-  SampleCounter interframe_delay_counter_video_ GUARDED_BY(crit_);
-  SampleCounter interframe_delay_counter_screenshare_ GUARDED_BY(crit_);
-  int64_t e2e_delay_max_ms_video_ GUARDED_BY(crit_);
-  int64_t e2e_delay_max_ms_screenshare_ GUARDED_BY(crit_);
-  int64_t interframe_delay_max_ms_video_  GUARDED_BY(crit_);
-  int64_t interframe_delay_max_ms_screenshare_  GUARDED_BY(crit_);
+  std::map<VideoContentType, ContentSpecificStats> content_specific_stats_
+      GUARDED_BY(crit_);
   MaxCounter freq_offset_counter_ GUARDED_BY(crit_);
   int64_t first_report_block_time_ms_ GUARDED_BY(crit_);
   ReportBlockStats report_block_stats_ GUARDED_BY(crit_);