Rename RTPVideoHeader.isFirstPacket to .is_first_packet_in_frame.

webrtc/modules/video_coding/packet.h

Index: webrtc/modules/video_coding/packet.h
diff --git a/webrtc/modules/video_coding/packet.h b/webrtc/modules/video_coding/packet.h
index 16f568504e6f34577ae0046d4d634212883ad002..fa3f4790dc92eec2ff43aa1adc7bcf66baba7ddf 100644
--- a/webrtc/modules/video_coding/packet.h
+++ b/webrtc/modules/video_coding/packet.h
@@ -39,7 +39,7 @@ class VCMPacket {
   FrameType frameType;
   VideoCodecType codec;
 
-  bool isFirstPacket;                // Is this first packet in a frame.
+  bool is_first_packet_in_frame;     // Is this first packet in a frame.
   VCMNaluCompleteness completeNALU;  // Default is kNaluIncomplete.
   bool insertStartCode;  // True if a start code should be inserted before this
                          // packet.