Improve curtain mode error message.

remoting/host/remoting_me2me_host.cc

Index: remoting/host/remoting_me2me_host.cc
diff --git a/remoting/host/remoting_me2me_host.cc b/remoting/host/remoting_me2me_host.cc
index 8cfdc5f85b07e57d787417a5967bfb31b5e50409..90a55a48dac83a1d306c57694513aa3d1d98ff79 100644
--- a/remoting/host/remoting_me2me_host.cc
+++ b/remoting/host/remoting_me2me_host.cc
@@ -212,7 +212,9 @@ class HostProcess
 
   void OnAuthFailed();
 
-  void RejectAuthenticatingClient();
+  void OnCurtainModeFailed();
+
+  void OnRemoteSessionSwitchedToConsole();
 
   // Invoked when the user uses the Disconnect windows to terminate
   // the sessions, or when the local session is activated in curtain mode.
@@ -312,9 +314,9 @@ HostProcess::HostProcess(scoped_ptr<ChromotingHostContext> context,
   // Create the platform-specific curtain-mode implementation.
   // TODO(wez): Create this on the network thread?
   curtain_ = CurtainMode::Create(
-      base::Bind(&HostProcess::OnDisconnectRequested,
+      base::Bind(&HostProcess::OnRemoteSessionSwitchedToConsole,
                  base::Unretained(this)),
-      base::Bind(&HostProcess::RejectAuthenticatingClient,
+      base::Bind(&HostProcess::OnCurtainModeFailed,
                  base::Unretained(this)));
 
   StartOnUiThread();
@@ -933,10 +935,15 @@ void HostProcess::OnAuthFailed() {
   Shutdown(kInvalidOauthCredentialsExitCode);
 }
 
-void HostProcess::RejectAuthenticatingClient() {
-  DCHECK(context_->network_task_runner()->BelongsToCurrentThread());
-  DCHECK(host_);
-  host_->RejectAuthenticatingClient();

[Jamie, 2012/11/28 23:52:32]

There's a comment on this method saying that it should only be used from
OnClientAuthenticated(), so I don't think it's the right thing to use here,
although it's not the cause of the bogus error message.

[rmsousa, 2012/11/29 00:11:14]

Right now this is only called when activating the curtain mode failed (so
perhaps OnCurtainModeActivationFailed would be more explicit), which is
ultimately done from an OnClientAuthenticated callback from
CurtainingHostObserver.

The problem with using OnDisconnectRequested() here is that it immediately
disconnects the session, and calls the OnClientDisconnected callback in all
HostObservers. This means that if it's called from an OnClientAuthenticated
handler, some HostObservers will receive the OnClientDisconnected callback
*before* the OnClientAuthenticated (and the CurtainingHostObserver will call
OnClientDisconnected *from* an OnClientAuthenticated callstack)

I'd prefer to change the messaging on the client side from "the PIN was wrong"
to something on the lines of "the host rejected your connection, due to a wrong
PIN or a host security policy", since there could be more policy-related reasons
why a host rejects a client during authentication (username policy, etc).

[Jamie, 2012/11/29 01:05:58]

which is
You're right. I'd forgotten that we are effectively calling it in the right
context, it's just not obvious from a cursory inspection of the code, and it
feels brittle to rely on it.
Yuck. Okay, I'll switch back to calling RejectAuthenticatingClient. Thanks for
the drive-by.
Since the most likely reason a user might see this message is that they've
entered an invalid PIN, I don't want to make the error message more complicated.

[Sergey Ulanov, 2012/11/30 01:09:39]

+1. A message that says "maybe your entered incorrect PIN or maybe something
else is wrong" is not helpful and we should avoid it.

+void HostProcess::OnCurtainModeFailed() {
+  LOG(ERROR) << "Curtain mode failed to activate. Closing connection.";
+  OnDisconnectRequested();
+}
+
+void HostProcess::OnRemoteSessionSwitchedToConsole() {
+  LOG(INFO) << "The remote session switched was to the console."
+             << " Closing connection.";
+  OnDisconnectRequested();
 }
 
 // Invoked when the user uses the Disconnect windows to terminate