Change var blah_blah -> blahBlah.

chrome/browser/resources/backloader/scripts/background.js

 // Copyright (c) 2012 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.
 
 function Loader(pages) {
   this.pages_ = pages;
   this.pagesLoaded_ = false;
   this.loadedCount_ = false;
 }
 
@@ skipping 46 matching lines @@
   onAlarm_: function(alarm) {
     if (alarm.name != this.ALARM_NAME)
       return;
 
     this.preparePages_();
   },
 
   onMessage_: function(event) {
     var msg = event.data;
     if (msg.method == 'validate') {
-      var reply_msg = {
+      var replyMsg = {
           method: 'validationResults',
           os: 'ChromeOS'
       };
-      event.source.postMessage(reply_msg, event.origin);
+      event.source.postMessage(replyMsg, event.origin);
     } else {
       console.log('#### Loader.onMessage_: unknown message');
     }
   },
 
   // Find an extension in the |list| with matching extension |id|.
   getExtensionById_: function(list, id) {
     for (var i = 0; i < list.length; i++) {
       if (list[i].id == id)
         return list[i];
@@ skipping 54 matching lines @@
     iframe.onload = function() {
       this.incrementLoadCounter_();
     }.bind(this);
     iframe.src = pageUrl;
     iframe.name = 'frame_' + index;
     document.body.appendChild(iframe);
   }
 };
 
 Loader.getInstance().initialize();