Parse termination reason and propagate the error to the Session interface.

remoting/protocol/session.h

Index: remoting/protocol/session.h
diff --git a/remoting/protocol/session.h b/remoting/protocol/session.h
index 920a681d685b5647776681d07baf19b51b610397..0697b16ebb632cbaafcbbc391bb668b0e10acc44 100644
--- a/remoting/protocol/session.h
+++ b/remoting/protocol/session.h
@@ -49,6 +49,14 @@ class Session : public base::NonThreadSafe {
     FAILED,
   };
 
+  enum Error {
+    OK = 0,
+    PEER_IS_OFFLINE,
+    SESSION_REJECTED,
+    INCOMPATIBLE_PROTOCOL,
+    CHANNEL_CONNECTION_ERROR,
+  };
+
   typedef Callback1<State>::Type StateChangeCallback;
   typedef base::Callback<void(net::StreamSocket*)> StreamChannelCallback;
   typedef base::Callback<void(net::Socket*)> DatagramChannelCallback;
@@ -60,6 +68,9 @@ class Session : public base::NonThreadSafe {
   // Must be called on the jingle thread only.
   virtual void SetStateChangeCallback(StateChangeCallback* callback) = 0;
 
+  // Returns error code for a failed session.
+  virtual Error error() = 0;
+
   // Creates new channels for this connection. The specified callback
   // is called when then new channel is created and connected. The
   // callback is called with NULL if connection failed for any reason.