[Cast,Android,Presentation API] Send messages back to the right clients, listen for messages sooner.

content/renderer/presentation/presentation_dispatcher.cc

Index: content/renderer/presentation/presentation_dispatcher.cc
diff --git a/content/renderer/presentation/presentation_dispatcher.cc b/content/renderer/presentation/presentation_dispatcher.cc
index d299c1abf019c3c9ce629ae781986b1f5dd04bed..268f1696dcae93a788f6c4d5f38eb9802207b487 100644
--- a/content/renderer/presentation/presentation_dispatcher.cc
+++ b/content/renderer/presentation/presentation_dispatcher.cc
@@ -346,9 +346,9 @@ void PresentationDispatcher::OnDefaultSessionStarted(
     return;
 
   if (!session_info.is_null()) {
+    presentation_service_->ListenForSessionMessages(session_info.Clone());

[imcheng, 2015/12/15 23:42:32]

This change is probably OK for desktop. As I mentioned in the bug, we can
consider moving this call into browser to avoid this IPC. But that can be done
separately.

[whywhat, 2015/12/16 12:31:20]

It seems to pass all the tests at least :)

Do you expect PD to just have a OnPresentationConnectionMessage then, similar to
state change, and the service impl would register itself for connection
messages?

[imcheng, 2015/12/16 19:24:36]

Yeah, PresentationServiceImpl will call back into PresentationServiceDelegate to
listen for state changes before sending the connection back to
PresentationDispatcher. That will simplify the interaction between this class
and PresentationServiceImpl.

     controller_->didStartDefaultSession(
-        new PresentationConnectionClient(session_info.Clone()));
-    presentation_service_->ListenForSessionMessages(session_info.Pass());
+        new PresentationConnectionClient(session_info.Pass()));
   }
 }
 
@@ -366,9 +366,9 @@ void PresentationDispatcher::OnSessionCreated(
   }
 
   DCHECK(!session_info.is_null());
+  presentation_service_->ListenForSessionMessages(session_info.Clone());
   callback->onSuccess(blink::adoptWebPtr(
-      new PresentationConnectionClient(session_info.Clone())));
-  presentation_service_->ListenForSessionMessages(session_info.Pass());
+      new PresentationConnectionClient(session_info.Pass())));
 }
 
 void PresentationDispatcher::OnConnectionStateChanged(