cros: Use AlertDialog for remora device requisition.

ui/webui/resources/js/cr/ui/dialogs.js

Index: ui/webui/resources/js/cr/ui/dialogs.js
diff --git a/ui/webui/resources/js/cr/ui/dialogs.js b/ui/webui/resources/js/cr/ui/dialogs.js
index ee9125fb7a8e8d97c1647c1bc5136dd41973a304..c8c4c97c7494a353e94a4d76adb58b2c63d10f62 100644
--- a/ui/webui/resources/js/cr/ui/dialogs.js
+++ b/ui/webui/resources/js/cr/ui/dialogs.js
@@ -91,7 +91,9 @@ cr.define('cr.ui.dialogs', function() {
 
   BaseDialog.prototype.onContainerKeyDown_ = function(event) {
     // Handle Escape.
-    if (event.keyCode == 27 && !this.cancelButton_.disabled) {
+    if (event.keyCode == 27 &&
+        !this.cancelButton_.disabled &&
+        !this.cancelButton_.hidden) {
       this.onCancelClick_(event);
       event.stopPropagation();
       // Prevent the event from being handled by the container of the dialog.
@@ -242,7 +244,8 @@ cr.define('cr.ui.dialogs', function() {
    */
   function AlertDialog(parentNode) {
     BaseDialog.apply(this, [parentNode]);
-    this.cancelButton_.style.display = 'none';
+    this.cancelButton_.hidden = true;
+    this.closeButton_.hidden = true;
   }
 
   AlertDialog.prototype = {__proto__: BaseDialog.prototype};