Add P2PDatagramSocket and P2PStreamSocket interfaces.

remoting/signaling/xmpp_signal_strategy.cc

Index: remoting/signaling/xmpp_signal_strategy.cc
diff --git a/remoting/signaling/xmpp_signal_strategy.cc b/remoting/signaling/xmpp_signal_strategy.cc
index 9833c6bbea9aeb08b8693b835933adacdf304eb7..51eae4bc62c75ac11de54e5c55b3309ec8d11867 100644
--- a/remoting/signaling/xmpp_signal_strategy.cc
+++ b/remoting/signaling/xmpp_signal_strategy.cc
@@ -362,9 +362,8 @@ void XmppSignalStrategy::Core::OnSocketConnected(int result) {
     return;
   }
 
-  writer_.reset(new BufferedSocketWriter());
-  writer_->Init(socket_.get(), base::Bind(&Core::OnNetworkError,
-                                          base::Unretained(this)));
+  writer_ = BufferedSocketWriter::CreateForSocket(
+      socket_.get(), base::Bind(&Core::OnNetworkError, base::Unretained(this)));
 
   XmppLoginHandler::TlsMode tls_mode;
   if (xmpp_server_config_.use_tls) {
@@ -406,9 +405,8 @@ void XmppSignalStrategy::Core::OnTlsConnected(int result) {
     return;
   }
 
-  writer_.reset(new BufferedSocketWriter());
-  writer_->Init(socket_.get(), base::Bind(&Core::OnNetworkError,
-                                          base::Unretained(this)));
+  writer_ = BufferedSocketWriter::CreateForSocket(
+      socket_.get(), base::Bind(&Core::OnNetworkError, base::Unretained(this)));
 
   login_handler_->OnTlsStarted();