Pick the DTLS handshake timeout based on the ICE RTT estimate

webrtc/p2p/base/icetransportinternal.h

Index: webrtc/p2p/base/icetransportinternal.h
diff --git a/webrtc/p2p/base/icetransportinternal.h b/webrtc/p2p/base/icetransportinternal.h
index 0ac7974f1de92db2f2bdd74ffeb0d9c9f6820cb1..7dd1993a1b37eb954196880dcfa483c7b66933fa 100644
--- a/webrtc/p2p/base/icetransportinternal.h
+++ b/webrtc/p2p/base/icetransportinternal.h
@@ -103,6 +103,10 @@ class IceTransportInternal : public rtc::PacketTransportInterface {
   // Returns the current stats for this connection.
   virtual bool GetStats(ConnectionInfos* infos) = 0;
 
+  // Returns RTT estimate over the currently active connection, or an empty
+  // rtc::Optional if there is none.
+  virtual rtc::Optional<int> GetRttEstimate() = 0;
+
   sigslot::signal1<IceTransportInternal*> SignalGatheringState;
 
   // Handles sending and receiving of candidates.