Revert of Change type of pid_diff (int16_t -> uint8_t) according to updates in RTP payload profile.

webrtc/modules/video_coding/main/source/jitter_buffer.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include "webrtc/modules/video_coding/main/source/jitter_buffer.h"
@@ skipping 150 matching lines @@
   return diff / kVideoPayloadTypeFrequency >= kSsCleanupIntervalSec;
 }
 
 void Vp9SsMap::AdvanceFront(uint32_t timestamp) {
   RTC_DCHECK(!ss_map_.empty());
   GofInfoVP9 gof = ss_map_.begin()->second;
   ss_map_.erase(ss_map_.begin());
   ss_map_[timestamp] = gof;
 }
 
-// TODO(asapersson): Update according to updates in RTP payload profile.
 bool Vp9SsMap::UpdatePacket(VCMPacket* packet) {
   uint8_t gof_idx = packet->codecSpecificHeader.codecHeader.VP9.gof_idx;
   if (gof_idx == kNoGofIdx)
     return false;  // No update needed.
 
   SsMap::iterator it;
   if (!Find(packet->timestamp, &it))
     return false;  // Corresponding SS not yet received.
 
   if (gof_idx >= it->second.num_frames_in_gof)
     return false;  // Assume corresponding SS not yet received.
 
   RTPVideoHeaderVP9* vp9 = &packet->codecSpecificHeader.codecHeader.VP9;
   vp9->temporal_idx = it->second.temporal_idx[gof_idx];
   vp9->temporal_up_switch = it->second.temporal_up_switch[gof_idx];
 
   // TODO(asapersson): Set vp9.ref_picture_id[i] and add usage.
   vp9->num_ref_pics = it->second.num_ref_pics[gof_idx];
-  for (uint8_t i = 0; i < it->second.num_ref_pics[gof_idx]; ++i) {
+  for (size_t i = 0; i < it->second.num_ref_pics[gof_idx]; ++i) {
     vp9->pid_diff[i] = it->second.pid_diff[gof_idx][i];
   }
   return true;
 }
 
 void Vp9SsMap::UpdateFrames(FrameList* frames) {
   for (const auto& frame_it : *frames) {
     uint8_t gof_idx =
         frame_it.second->CodecSpecific()->codecSpecific.VP9.gof_idx;
     if (gof_idx == kNoGofIdx) {
@@ skipping 1130 matching lines @@
   }
   // Evaluate if the RTT is higher than |high_rtt_nack_threshold_ms_|, and in
   // that case we don't wait for retransmissions.
   if (high_rtt_nack_threshold_ms_ >= 0 &&
       rtt_ms_ >= high_rtt_nack_threshold_ms_) {
     return false;
   }
   return true;
 }
 }  // namespace webrtc