[filemanager] Implementing undo delete functionality.

chrome/browser/resources/file_manager/js/directory_contents.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.
 
 /**
  * @constructor
  * @param {MetadataCache} metadataCache Metadata cache service.
  * @param {cr.ui.ArrayDataModel} fileList The file list.
  * @param {boolean} showHidden If files starting with '.' are shown.
  */
 function FileListContext(metadataCache, fileList, showHidden) {
   /**
    * @type {MetadataCache}
    */
   this.metadataCache = metadataCache;
   /**
    * @type {cr.ui.ArrayDataModel}
    */
   this.fileList = fileList;
   /**
    * @type Object.<string, Function>
    * @private
    */
   this.filters_ = {};
   this.setFilterHidden(!showHidden);
+
+  // Do not show entries marked as 'deleted'.
+  this.addFilter('deleted', function(entry) {
+    var internal = this.metadataCache.getCached(entry, 'internal');
+    return !(internal && internal.deleted);
+  }.bind(this));
 }
 
 /**
  * @param {string} name Filter identifier.
  * @param {Function(Entry)} callback A filter — a function receiving an Entry,
  *     and returning bool.
  */
 FileListContext.prototype.addFilter = function(name, callback) {
   this.filters_[name] = callback;
 };
@@ skipping 551 matching lines @@
   }.bind(this);
 
   getNextChunk();
 };
 
 /**
  * We get results for each directory in one go in scanDirectory_.
  */
 DirectoryContentsLocalSearch.prototype.readNextChunk = function() {
 };