[Webapp Refactor] Cleans up the ClientSession.EventHandler interface.

remoting/webapp/app_remoting/js/app_remoting_activity.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 /**
  * Type definition for the RunApplicationResponse returned by the API.
  * @typedef {{
@@ skipping 122 matching lines @@
               {fetchThirdPartyToken: fetchThirdPartyToken});
       var that = this;
 
       this.sessionFactory_.createSession(this).then(
         function(/** remoting.ClientSession */ session) {
           that.session_ = session;
           session.logHostOfflineErrors(true);
           session.connect(host, credentialsProvider);
       });
     } else if (response && response.status == 'pending') {
-      this.onError(new remoting.Error(
+      this.onConnectionFailed(new remoting.Error(
           remoting.Error.Tag.SERVICE_UNAVAILABLE));
     }
   } else {
     console.error('Invalid "runApplication" response from server.');
-    this.onError(remoting.Error.fromHttpStatus(xhrResponse.status));
+    this.onConnectionFailed(remoting.Error.fromHttpStatus(xhrResponse.status));
   }
 };
 
 /**
  * @param {remoting.ConnectionInfo} connectionInfo
  */
 remoting.AppRemotingActivity.prototype.onConnected = function(connectionInfo) {
   this.connectedView_ = new remoting.AppConnectedView(
       document.getElementById('client-container'), connectionInfo);
 
   var idleDetector = new remoting.IdleDetector(
       document.getElementById('idle-dialog'), this.stop.bind(this));
 
   // Map Cmd to Ctrl on Mac since hosts typically use Ctrl for keyboard
   // shortcuts, but we want them to act as natively as possible.
   if (remoting.platformIsMac()) {
     connectionInfo.plugin().setRemapKeys('0x0700e3>0x0700e0,0x0700e7>0x0700e4');
   }
 };
 
-remoting.AppRemotingActivity.prototype.onDisconnected = function() {
+/**
+ * @param {remoting.Error} error
+ */
+remoting.AppRemotingActivity.prototype.onDisconnected = function(error) {
+  if (error.isNone()) {
+    chrome.app.window.current().close();
+  } else {
+    this.showErrorMessage_(error);
+  }
   this.cleanup_();
-  chrome.app.window.current().close();
 };
 
 /**
  * @param {!remoting.Error} error
  */
 remoting.AppRemotingActivity.prototype.onConnectionFailed = function(error) {
-  this.onError(error);
+  remoting.LoadingWindow.close();
+  this.showErrorMessage_(error);
+  this.cleanup_();
 };
 
 /**
  * @param {!remoting.Error} error The error to be localized and displayed.
+ * @private
  */
-remoting.AppRemotingActivity.prototype.onError = function(error) {
+remoting.AppRemotingActivity.prototype.showErrorMessage_ = function(error) {
   console.error('Connection failed: ' + error.toString());
-  remoting.LoadingWindow.close();
   remoting.MessageWindow.showErrorMessage(
       chrome.i18n.getMessage(/*i18n-content*/'CONNECTION_FAILED'),
       chrome.i18n.getMessage(error.getTag()));
-  this.cleanup_();
 };
 
 })();