Reland of Rename RTPVideoHeader.isFirstPacket to .is_first_packet_in_frame.

webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc b/webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc
index 15a1d8b1520f094a60611b7469bdf4b2da33fdfe..99f5d6ca5413598901b7423137c354084c1850b1 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_format_h264.cc
@@ -393,7 +393,7 @@ bool RtpDepacketizerH264::ProcessStapAOrSingleNalu(
   parsed_payload->type.Video.width = 0;
   parsed_payload->type.Video.height = 0;
   parsed_payload->type.Video.codec = kRtpVideoH264;
-  parsed_payload->type.Video.isFirstPacket = true;
+  parsed_payload->type.Video.is_first_packet_in_frame = true;
   RTPVideoHeaderH264* h264_header =
       &parsed_payload->type.Video.codecHeader.H264;
 
@@ -614,7 +614,7 @@ bool RtpDepacketizerH264::ParseFuaNalu(
   parsed_payload->type.Video.width = 0;
   parsed_payload->type.Video.height = 0;
   parsed_payload->type.Video.codec = kRtpVideoH264;
-  parsed_payload->type.Video.isFirstPacket = first_fragment;
+  parsed_payload->type.Video.is_first_packet_in_frame = first_fragment;
   RTPVideoHeaderH264* h264 = &parsed_payload->type.Video.codecHeader.H264;
   h264->packetization_type = kH264FuA;
   h264->nalu_type = original_nal_type;