[filemanager] Set default sort to Date.

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.
 
 /**
  * FileManager constructor.
  *
  * FileManager objects encapsulate the functionality of the file selector
  * dialogs, as well as the full screen file manager application (though the
  * latter is not yet implemented).
@@ skipping 485 matching lines @@
       this.directoryModel_.addEventListener('directory-changed',
           this.setupCurrentDirectoryPostponed_);
     } else {
       this.setupCurrentDirectory_(
           invokeHandler, true /* blankWhileOpeningAFile */);
     }
 
     this.summarizeSelection_();
 
     var sortField =
-        window.localStorage['sort-field-' + this.dialogType_] || 'cachedMtime_';
+        window.localStorage['sort-field-' + this.dialogType_] ||
+        'modificationTime';
     var sortDirection =
         window.localStorage['sort-direction-' + this.dialogType_] || 'desc';
     this.directoryModel_.fileList.sort(sortField, sortDirection);
 
     this.refocus();
 
     this.metadataProvider_ =
         new MetadataProvider(this.filesystem_.root.toURL());
 
     // PyAuto tests monitor this state by polling this variable
@@ skipping 3813 matching lines @@
 
       handleSplitterDragEnd: function(e) {
         Splitter.prototype.handleSplitterDragEnd.apply(this, arguments);
         this.ownerDocument.documentElement.classList.remove('col-resize');
       }
     };
 
     customSplitter.decorate(splitterElement);
   };
 })();