Don't call expensive toString() in onAccessibilityEvent

chrome/renderer/resources/extensions/automation/automation_node.js

 // Copyright 2014 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.
 
 var AutomationEvent = require('automationEvent').AutomationEvent;
 var automationInternal =
     require('binding').Binding.create('automationInternal').generate();
 var IsInteractPermitted =
     requireNative('automationInternal').IsInteractPermitted;
 
@@ skipping 350 matching lines @@
       return false;
     }
 
     var targetNode = this.get(eventParams.targetID);
     if (targetNode) {
       var targetNodeImpl = privates(targetNode).impl;
       targetNodeImpl.dispatchEvent(eventParams.eventType);
     } else {
       logging.WARNING('Got ' + eventParams.eventType +
                       ' event on unknown node: ' + eventParams.targetID +
-                      '; this: ' + this.toString());
+                      '; this: ' + this.id);
     }
     return true;
   },
 
   toString: function() {
     function toStringInternal(node, indent) {
       if (!node)
         return '';
       var output =
           new Array(indent).join(' ') +
@@ skipping 226 matching lines @@
                                                'root'] });
 
 var AutomationRootNode = utils.expose('AutomationRootNode',
                                       AutomationRootNodeImpl,
                                       { superclass: AutomationNode,
                                         functions: ['load'],
                                         readonly: ['loaded'] });
 
 exports.AutomationNode = AutomationNode;
 exports.AutomationRootNode = AutomationRootNode;