Propagate connection state from networking layer to UI.

remoting/protocol/connection_to_host.h

Index: remoting/protocol/connection_to_host.h
diff --git a/remoting/protocol/connection_to_host.h b/remoting/protocol/connection_to_host.h
index 4eb7d15251bd1fb7eec757f06130597658f94cf2..d064b64bf5a47171fc67c6cf7a6ee7e0eadc3b6f 100644
--- a/remoting/protocol/connection_to_host.h
+++ b/remoting/protocol/connection_to_host.h
@@ -64,6 +64,9 @@ class ConnectionToHost : public SignalStrategy::Listener,
 
     // Called when state of the connection changes.
     virtual void OnConnectionState(State state, ErrorCode error) = 0;
+
+    // Called to indicate inactive connection.

[Wez, 2012/07/16 18:51:23]

What does it mean for a connection to be "inactive"? I'd assume it means that
the client has not sent any input events for a while, or the host has sent no
video updates, but in the context of this CL it means that one or more channels
are not "connected"?

[Sergey Ulanov, 2012/07/17 01:17:17]

Done.

+    virtual void OnConnectionInactive(bool inactive) = 0;

[Wez, 2012/07/16 18:51:23]

Why not expose this as a new connection state?

[Sergey Ulanov, 2012/07/17 01:17:17]

I considered it, but I don't think it would be useful to expose it as part of
State:
 1. It's not really a part of the connection state machine implemented in this
class,
 2. Older version of the webapp may not know how to handle the new state state,
 3. Not all client will care about not-ready state,
 4. Later we may want to replace it with something that exposes more information
about connection health (e.g. delays, etc.).

   };
 
   ConnectionToHost(bool allow_nat_traversal);
@@ -104,6 +107,8 @@ class ConnectionToHost : public SignalStrategy::Listener,
   virtual void OnSessionStateChange(Session::State state) OVERRIDE;
   virtual void OnSessionRouteChange(const std::string& channel_name,
                                     const TransportRoute& route) OVERRIDE;
+  virtual void OnSessionInactive(const std::string& channel_name,
+                                 bool inactive) OVERRIDE;
 
   // Return the current state of ConnectionToHost.
   State state() const;