[filemanager] Implementing undo delete functionality.

chrome/browser/resources/file_manager/js/file_copy_manager_wrapper.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.
 
 var fileCopyManagerWrapper = null;
 
 /**
  * While FileCopyManager is run in the background page, this class is used to
  * communicate with it.
  * @constructor
@@ skipping 31 matching lines @@
     return null;
   return bg.FileCopyManager.getInstance(this.root_);
 };
 
 /**
  * Load background page and call callback with copy manager as an argument.
  * @private
  * @param {Function} callback Function with FileCopyManager as a parameter.
  */
 FileCopyManagerWrapper.prototype.getCopyManagerAsync_ = function(callback) {
-  chrome.runtime.getBackgroundPage(
-      function(bg) {
-        callback(bg.FileCopyManager.getInstance(this.root_));
-      }.bind(this));
+  var MAX_RETRIES = 10;
+  var TIMEOUT = 100;
+
+  var root = this.root_;
+  var retries = 0;
+
+  function tryOnce() {
+    chrome.runtime.getBackgroundPage(function(bg) {
+      if (bg) {
+        callback(bg.FileCopyManager.getInstance(root));
+        return;
+      }
+      if (++retries < MAX_RETRIES)
+        setTimeout(tryOnce, TIMEOUT);
+    });
+  }
+
+  tryOnce();
 };
 
 /**
  * Called be FileCopyManager to raise an event in this instance of FileManager.
  * @param {string} eventName Event name.
  * @param {Object} eventArgs Arbitratry field written to event object.
  */
 FileCopyManagerWrapper.prototype.onEvent = function(eventName, eventArgs) {
   var event = new cr.Event(eventName);
   for (var arg in eventArgs)
@@ skipping 28 matching lines @@
     totalBytes: 0,
 
     percentage: NaN,
     pendingCopies: 0,
     pendingMoves: 0,
     filename: ''  // In case pendingItems == 1
   };
 };
 
 /**
- * Request that the current copy queue be abandoned.
- * @param {Function} opt_callback On cancel.
+ * Decorates a FileCopyManager method, so it will be executed after initializing
+ * the FileCopyManager instance in background page.
+ * @param {string} method The method name.
  */
-FileCopyManagerWrapper.prototype.requestCancel = function(opt_callback) {
-  this.getCopyManagerAsync_(
-      function(cm) {
-        cm.requestCancel(opt_callback);
-      });
+FileCopyManagerWrapper.decorateAsyncMethod = function(method) {
+  FileCopyManagerWrapper.prototype[method] = function() {
+    var args = Array.prototype.slice.call(arguments);
+    this.getCopyManagerAsync_(function(cm) {
+      cm[method].apply(cm, args);
+    });
+  };
 };
 
-/**
- * Convert string in clipboard to entries and kick off pasting.
- * @param {Object} clipboard Clipboard contents.
- * @param {string} targetPath Target path.
- * @param {boolean} targetOnGData If target is on GDrive.
- */
-FileCopyManagerWrapper.prototype.paste = function(clipboard, targetPath,
-                                                  targetOnGData) {
-  this.getCopyManagerAsync_(
-      function(cm) {
-        cm.paste(clipboard, targetPath, targetOnGData);
-      });
-};
-
+FileCopyManagerWrapper.decorateAsyncMethod('requestCancel');
+FileCopyManagerWrapper.decorateAsyncMethod('paste');
+FileCopyManagerWrapper.decorateAsyncMethod('deleteEntries');
+FileCopyManagerWrapper.decorateAsyncMethod('forceDeleteTask');
+FileCopyManagerWrapper.decorateAsyncMethod('cancelDeleteTask');