[File Manager] Fix history state for GData folder navigation

chrome/browser/resources/file_manager/js/file_manager.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.
 
 // Setting the src of an img to an empty string can crash the browser, so we
 // use an empty 1x1 gif instead.
 
 /**
  * FileManager constructor.
  *
@@ skipping 3760 matching lines @@
     this.updateCommonActionButtons_();
     this.updateOkButton_();
     this.updateBreadcrumbs_();
     this.updateColumnModel_();
 
     // Updated when a user clicks on the label of a file, used to detect
     // when a click is eligible to trigger a rename.  Can be null, or
     // an object with 'path' and 'date' properties.
     this.lastLabelClick_ = null;
 
-    var dirEntry = event.newDirEntry;
-    this.updateLocation_(event.initial, dirEntry.fullPath);
+    // Sometimes we rescan the same directory, do not update the location then.

[SeRya, 2012/04/13 12:32:11]

I think it's a wrong fix.

Rescan doesn't cause directory change. There is no sense not only in updating
location, but also in updating buttons and breadcrumbs. 'directory-change'
mustn't be fired if event.newDirEntry.fullPath ==
event.previousDirEntry.fullPath.

Please, explain why two directory-change happen only on gdata? It sounds
suspicious for me. It could be a sign of a hidden bug.

+    if (event.newDirEntry.fullPath != event.previousDirEntry.fullPath) {
+      this.updateLocation_(event.initial, event.newDirEntry.fullPath);
+    }
 
     this.checkFreeSpace_(this.getCurrentDirectory());
 
     // TODO(dgozman): title may be better than this.
     this.document_.title = this.getCurrentDirectory().substr(1);
 
     var self = this;
 
     if (this.watchedDirectoryUrl_) {
       if (this.watchedDirectoryUrl_ != event.previousDirEntry.toURL()) {
@@ skipping 904 matching lines @@
 
     chrome.fileBrowserPrivate.setGDataPreferences(changeInfo);
 
     if (oldValue) {
       event.target.removeAttribute('checked');
     } else {
       event.target.setAttribute('checked', 'checked');
     }
   };
 })();