Add a new GetNegotiatedProtocol method to StreamSocket and implement in all subclasses.

jingle/notifier/base/proxy_resolving_client_socket.cc

Index: jingle/notifier/base/proxy_resolving_client_socket.cc
diff --git a/jingle/notifier/base/proxy_resolving_client_socket.cc b/jingle/notifier/base/proxy_resolving_client_socket.cc
index 5130100b013dece0667cd0612d6b3084733603c4..ab89ffbd81f9e9de0bb5d60ad82a71c6ff8f6dff 100644
--- a/jingle/notifier/base/proxy_resolving_client_socket.cc
+++ b/jingle/notifier/base/proxy_resolving_client_socket.cc
@@ -366,6 +366,13 @@ base::TimeDelta ProxyResolvingClientSocket::GetConnectTimeMicros() const {
   return base::TimeDelta::FromMicroseconds(-1);
 }
 
+net::NextProto ProxyResolvingClientSocket::GetNegotiatedProtocol() const {
+  if (transport_.get() && transport_->socket())
+    return transport_->socket()->GetNegotiatedProtocol();
+  NOTREACHED();
+  return net::kProtoUnknown;
+}
+
 void ProxyResolvingClientSocket::CloseTransportSocket() {
   if (transport_.get() && transport_->socket())
     transport_->socket()->Disconnect();