Revert "Add fine grained dropped video frames counters on sending side"

This reverts commit 4b1a363e4c238f2e1ec2d8a9ce1f819f59d710ce.

Reason for revert: Breaks dependent android projects.

Original change's description:
> Add fine grained dropped video frames counters on sending side
> 
> 4 new counters added to SendStatisticsProxy and reported to UMA and logs.
> 
> Bug: webrtc:8355
> Change-Id: Idf9b8dfc295c92821e058a97cb3894dc6a446082
> Reviewed-on: https://webrtc-review.googlesource.com/12260
> Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
> Reviewed-by: Stefan Holmer <stefan@webrtc.org>
> Reviewed-by: Erik Språng <sprang@webrtc.org>
> Reviewed-by: Taylor Brandstetter <deadbeef@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#20347}

TBR=deadbeef@webrtc.org,ilnik@webrtc.org,sprang@webrtc.org,stefan@webrtc.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: webrtc:8355
Change-Id: I59b02f4eb77abad7ff1fbcbfa61844918c95d723
Reviewed-on: https://webrtc-review.googlesource.com/14500
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20378}
diff --git a/modules/video_coding/generic_encoder.h b/modules/video_coding/generic_encoder.h
index 2cdf664..9b003d6 100644
--- a/modules/video_coding/generic_encoder.h
+++ b/modules/video_coding/generic_encoder.h
@@ -12,7 +12,7 @@
 #define MODULES_VIDEO_CODING_GENERIC_ENCODER_H_
 
 #include <stdio.h>
-#include <list>
+#include <map>
 #include <vector>
 
 #include "modules/video_coding/include/video_codec_interface.h"
@@ -71,16 +71,9 @@
   EncodedImageCallback* const post_encode_callback_;
   media_optimization::MediaOptimization* const media_opt_;
 
-  struct EncodeStartTimeRecord {
-    EncodeStartTimeRecord(int64_t capture_time, int64_t encode_start_time)
-        : capture_time_ms(capture_time),
-          encode_start_time_ms(encode_start_time) {}
-    int64_t capture_time_ms;
-    int64_t encode_start_time_ms;
-  };
   struct TimingFramesLayerInfo {
     size_t target_bitrate_bytes_per_sec = 0;
-    std::list<EncodeStartTimeRecord> encode_start_list;
+    std::map<int64_t, int64_t> encode_start_time_ms;
   };
   // Separate instance for each simulcast stream or spatial layer.
   std::vector<TimingFramesLayerInfo> timing_frames_info_
@@ -118,6 +111,7 @@
   int32_t SetPeriodicKeyFrames(bool enable);
   int32_t RequestFrame(const std::vector<FrameType>& frame_types);
   bool InternalSource() const;
+  void OnDroppedFrame();
   bool SupportsNativeHandle() const;
 
  private: