Revert of Rename RTPVideoHeader.isFirstPacket to .is_first_packet_in_frame.

webrtc/modules/video_coding/nack_module.cc

 /*
  *  Copyright (c) 2016 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.
  */
 
@@ skipping 48 matching lines @@
 int NackModule::OnReceivedPacket(const VCMPacket& packet) {
   rtc::CritScope lock(&crit_);
   if (!running_)
     return -1;
   uint16_t seq_num = packet.seqNum;
   // TODO(philipel): When the packet includes information whether it is
   //                 retransmitted or not, use that value instead. For
   //                 now set it to true, which will cause the reordering
   //                 statistics to never be updated.
   bool is_retransmitted = true;
-  bool is_keyframe =
-      packet.is_first_packet_in_frame && packet.frameType == kVideoFrameKey;
+  bool is_keyframe = packet.isFirstPacket && packet.frameType == kVideoFrameKey;
 
   if (!initialized_) {
     newest_seq_num_ = seq_num;
     if (is_keyframe)
       keyframe_list_.insert(seq_num);
     initialized_ = true;
     return 0;
   }
 
   // Since the |newest_seq_num_| is a packet we have actually received we know
@@ skipping 181 matching lines @@
   reordering_histogram_.Add(diff);
 }
 
 int NackModule::WaitNumberOfPackets(float probability) const {
   if (reordering_histogram_.NumValues() == 0)
     return 0;
   return reordering_histogram_.InverseCdf(probability);
 }
 
 }  // namespace webrtc