Revert of Rename RTPVideoHeader.isFirstPacket to .is_first_packet_in_frame.

webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc

 /*
  *  Copyright (c) 2014 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 371 matching lines @@
   parsed_payload->payload_length = length_;
   return true;
 }
 
 bool RtpDepacketizerH264::ProcessStapAOrSingleNalu(
     ParsedPayload* parsed_payload,
     const uint8_t* payload_data) {
   parsed_payload->type.Video.width = 0;
   parsed_payload->type.Video.height = 0;
   parsed_payload->type.Video.codec = kRtpVideoH264;
-  parsed_payload->type.Video.is_first_packet_in_frame = true;
+  parsed_payload->type.Video.isFirstPacket = true;
   RTPVideoHeaderH264* h264_header =
       &parsed_payload->type.Video.codecHeader.H264;
 
   const uint8_t* nalu_start = payload_data + kNalHeaderSize;
   const size_t nalu_length = length_ - kNalHeaderSize;
   uint8_t nal_type = payload_data[0] & kTypeMask;
   std::vector<size_t> nalu_start_offsets;
   if (nal_type == H264::NaluType::kStapA) {
     // Skip the StapA header (StapA NAL type + length).
     if (length_ <= kStapAHeaderSize) {
@@ skipping 200 matching lines @@
   }
 
   if (original_nal_type == H264::NaluType::kIdr) {
     parsed_payload->frame_type = kVideoFrameKey;
   } else {
     parsed_payload->frame_type = kVideoFrameDelta;
   }
   parsed_payload->type.Video.width = 0;
   parsed_payload->type.Video.height = 0;
   parsed_payload->type.Video.codec = kRtpVideoH264;
-  parsed_payload->type.Video.is_first_packet_in_frame = first_fragment;
+  parsed_payload->type.Video.isFirstPacket = first_fragment;
   RTPVideoHeaderH264* h264 = &parsed_payload->type.Video.codecHeader.H264;
   h264->packetization_type = kH264FuA;
   h264->nalu_type = original_nal_type;
   if (first_fragment) {
     h264->nalus[h264->nalus_length] = nalu;
     h264->nalus_length = 1;
   }
   return true;
 }
 
 }  // namespace webrtc