Refactor the Photo Editor to enable new feature work

chrome/browser/resources/file_manager/js/util.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.
 
 /**
  * Namespace for utility functions.
  */
 var util = {};
 
 /**
@@ skipping 551 matching lines @@
 /**
  * Makes filesystem: URL from the path.
  * @param {string} path File or directory path.
  * @return {string} URL.
  */
 util.makeFilesystemUrl = function(path) {
   return 'filesystem:' + chrome.extension.getURL('external' + path);
 };
 
 /**
+ * @return {string} Id of the current Chrome extension.
+ */
+util.getExtensionId = function() {
+  return chrome.extension.getURL('').split('/')[2];
+};
+
+/**
  * Traverses a tree up to a certain depth.
  * @param {FileEntry} root Root entry.
  * @param {function(Array.<Entry>)} callback The callback is called at the very
  *     end with a list of entries found.
  * @param {number?} max_depth Maximum depth. Pass zero to traverse everything.
  */
 util.traverseTree = function(root, callback, max_depth) {
   if (root.isFile) {
     callback([root]);
     return;
@@ skipping 49 matching lines @@
  * Equivilant to loadTimeData.getStringF(id, ...).
  *
  * @param {string} id The id of the string to return.
  * @param {...string} var_args The values to replace into the string.
  * @return {string} The translated string with replaced values.
  */
 function strf(id, var_args) {
   return loadTimeData.getStringF.apply(loadTimeData, arguments);
 }
 
+/**
+ * A shortcut function to create a child element with given tag and class.
+ *
+ * @param {HTMLElement} parent Parent element.
+ * @param {string} opt_className Class name.
+ * @param {string} opt_tag Element tag, DIV is omitted.
+ * @return {Element} Newly created element.
+ */
+function createChild(parent, opt_className, opt_tag) {
+  var child = parent.ownerDocument.createElement(opt_tag || 'div');
+  if (opt_className)
+    child.className = opt_className;
+  parent.appendChild(child);
+  return child;
+}