Simplify directory initialization in Files app.

chrome/browser/resources/file_manager/foreground/js/file_tasks.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.
 
 'use strict';
 
 /**
  * This object encapsulates everything related to tasks execution.
  *
  * @param {FileManager} fileManager FileManager instance.
@@ skipping 624 matching lines @@
   var allEntries =
       fm.getAllEntriesInCurrentDirectory().filter(FileType.isImageOrVideo);
 
   var galleryFrame = fm.document_.createElement('iframe');
   galleryFrame.className = 'overlay-pane';
   galleryFrame.scrolling = 'no';
   galleryFrame.setAttribute('webkitallowfullscreen', true);
 
   if (this.params_ && this.params_.gallery) {
     // Remove the Gallery state from the location, we do not need it any more.
-    util.updateAppState(null /* keep path */, '' /* remove search. */);
+    // TODO(mtomasz): Consider keeping the selection path.
+    util.updateAppState(
+        null, /* keep current directory */
+        '', /* remove current selection */
+        '' /* remove search. */);
   }
 
-  var savedAppState = window.appState;
+  var savedAppState = JSON.parse(JSON.stringify(window.appState));
   var savedTitle = document.title;
 
   // Push a temporary state which will be replaced every time the selection
   // changes in the Gallery and popped when the Gallery is closed.
   util.updateAppState();
 
   var onBack = function(selectedEntries) {
     fm.directoryModel.selectEntries(selectedEntries);
     fm.closeFilePopup();  // Will call Gallery.unload.
     window.appState = savedAppState;
@@ skipping 194 matching lines @@
       items, defaultIdx,
       function(item) {
         onSuccess(item.task);
       });
 };
 
 FileTasks.decorate('display');
 FileTasks.decorate('updateMenuItem');
 FileTasks.decorate('execute');
 FileTasks.decorate('executeDefault');