This CL adds methods to manipulate RTP header extension, particularly

content/browser/renderer_host/p2p/socket_host.h

Index: content/browser/renderer_host/p2p/socket_host.h
diff --git a/content/browser/renderer_host/p2p/socket_host.h b/content/browser/renderer_host/p2p/socket_host.h
index 46fcde5b7d56a22a815f1a0cf850b2fa538c4252..13b0384cefec773f33843d4d61db9a53bc57011a 100644
--- a/content/browser/renderer_host/p2p/socket_host.h
+++ b/content/browser/renderer_host/p2p/socket_host.h
@@ -53,7 +53,9 @@ class CONTENT_EXPORT P2PSocketHost {
   virtual bool SetOption(P2PSocketOption option, int value) = 0;
 
  protected:
-  friend class P2PSocketHostTcpTestBase;
+
+  void MaybeUpdatePacketSendTimeExtn(char* data, int length,

[Solis, 2014/02/26 15:49:34]

AFAICT none of the methods you've added need to access state in the class.
Therefore they should be pulled out from the class and into a namespace instead
(or at the very least be made static). By doing so there would be no need to
subclass P2PSocketHost in the test.

[Mallinath (Gone from Chromium), 2014/02/26 19:59:20]

That's a good point.

+                                     const talk_base::PacketOptions& options);
 
   // TODO(mallinath) - Remove this below enum and use one defined in
   // libjingle/souce/talk/p2p/base/stun.h
@@ -97,6 +99,17 @@ class CONTENT_EXPORT P2PSocketHost {
                                 StunMessageType* type);
   static bool IsRequestOrResponse(StunMessageType type);
 
+  bool MaybeUpdateRtpSendTimeExtn(char* rtp, int length,
+                                  int extension_id);
+  bool GetRtpPacketStartPositionAndLength(char* data, int length,
+                                          int* rtp_start_pos,
+                                          int* rtp_packet_length);
+  bool ValidateRtpHeader(char* rtp, int length);
+  void UpdateSendTimeExtnValue(char* data, int len);

[Solis, 2014/02/26 15:49:34]

We are using the names

PacketSendTimeExtn
RtpSendTimeExtn
SendTimeExtn
and in the .cc also 
AbsSendTimeExtn

to refer to the same header extension. Can we stick to a single nomenclature? I
would prefer AbsoluteSenderTimeExtension, or if you must abbreviate,
AbsSendTimeExtn.

[Mallinath (Gone from Chromium), 2014/02/26 19:59:20]

Done. Using AbsSendTimeExtn.

+
+  void MaybeUpdateRtpAuthTag(char* packet, int len,
+                             const talk_base::PacketOptions& options);
+
   IPC::Sender* message_sender_;
   int id_;
   State state_;