Refactor SignalStrategy so that it can be reused for multiple connections.

remoting/protocol/pepper_session.cc

Index: remoting/protocol/pepper_session.cc
diff --git a/remoting/protocol/pepper_session.cc b/remoting/protocol/pepper_session.cc
index 8eabb09b310757bbda971b17eb5702eef4f2e97a..2e5241ed8645940689edec121c455d017f3ed518 100644
--- a/remoting/protocol/pepper_session.cc
+++ b/remoting/protocol/pepper_session.cc
@@ -78,7 +78,7 @@ void PepperSession::StartConnection(
   // Send session-initiate message.
   JingleMessage message(peer_jid_, JingleMessage::SESSION_INITIATE,
                         session_id_);
-  message.from = session_manager_->local_jid_;
+  message.from = session_manager_->signal_strategy_->GetLocalJid();
   message.description.reset(
       new ContentDescription(candidate_config_->Clone(),
                              authenticator_->GetNextMessage()));