[Chromoting] Fix broken OK/Cancel button in loading window.

remoting/webapp/base/js/message_window.js

Index: remoting/webapp/base/js/message_window.js
diff --git a/remoting/webapp/base/js/message_window.js b/remoting/webapp/base/js/message_window.js
index 2355b3e5390af93dd4d3bf3d79dbf4c67be84ad3..d80c2053f9407ce7987946e8e595faaa6dc4febc 100644
--- a/remoting/webapp/base/js/message_window.js
+++ b/remoting/webapp/base/js/message_window.js
@@ -21,7 +21,7 @@ function MessageWindowImpl() {
 
 /**
  * @param {Window} parentWindow The id of the window that showed the message.
- * @param {string} messageId The identifier of the message, as supplied by the
+ * @param {number} messageId The identifier of the message, as supplied by the
  *     parent.
  * @param {number} result 0 if window was closed without pressing a button;
  *     otherwise the index of the button pressed (e.g., 1 = primary).
@@ -125,17 +125,15 @@ MessageWindowImpl.prototype.onMessage_ = function(event) {
         infoboxDiv.hidden = true;
       }
 
-      var messageIdStr = messageId.toString();
-
       this.initButton_(
           button,
           buttonLabel,
-          this.sendReply_.bind(this, event.source, messageIdStr, 1));
+          this.sendReply_.bind(this, event.source, messageId, 1));
 
       this.initButton_(
           cancelButton,
           cancelButtonLabel,
-          this.sendReply_.bind(this, event.source, messageIdStr, 0));
+          this.sendReply_.bind(this, event.source, messageId, 0));
 
       var buttonToFocus = (cancelButtonLabel) ? cancelButton : button;
       buttonToFocus.focus();
@@ -145,7 +143,7 @@ MessageWindowImpl.prototype.onMessage_ = function(event) {
       // Note that when a button is pressed, this will result in sendReply_
       // being called multiple times (once for the button, once for close).
       chrome.app.window.current().onClosed.addListener(
-          this.sendReply_.bind(this, event.source, messageIdStr, 0));
+          this.sendReply_.bind(this, event.source, messageId, 0));
 
       this.updateSize_();
       chrome.app.window.current().show();