Add a libfuzzer for RtpHeaderParser.

webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h

Index: webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
diff --git a/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h b/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
index 8875d65081829751572270a4f9788b5f67874c4d..2c2f9fa20ef3021327b631e7334db967e114e46f 100644
--- a/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
+++ b/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
@@ -60,6 +60,7 @@ enum StorageType {
   kAllowRetransmission
 };
 
+const int kNumberOfRtpHeaderExtensions = 7;

[phoglund, 2016/06/15 08:20:25]

Maybe just add this as the last entry in the enum? It will get the value 7 and
automatically update when new entries are added. Have a blank line between it
and the others to signfify it's a special entry.

You'll have to bring in an OWNER for rtp_rtcp anyway, and they probably know
better than me.

[katrielc, 2016/06/15 09:05:30]

The problem with adding it to the enum is that it's then a valid enum value,
which you don't want.

(For example, you'd have to change all the switches in the rest of the code to
handle it.)

 enum RTPExtensionType {
   kRtpExtensionNone,
   kRtpExtensionTransmissionTimeOffset,