Fix trivial type-check errors in file_manager.

ui/file_manager/file_manager/foreground/js/ui/scrollbar.js

 // Copyright (c) 2013 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';
 
 /**
  * Creates a new scroll bar element.
  * @extends {HTMLDivElement}
  * @constructor
  */
 var ScrollBar = cr.ui.define('div');
 
 /**
  * Mode of the scrollbar. As for now, only vertical scrollbars are supported.
- * @type {number}
+ * @enum {number}
  */
 ScrollBar.Mode = {
   VERTICAL: 0,
   HORIZONTAL: 1
 };
 
 ScrollBar.prototype = {
   set mode(value) {
     this.mode_ = value;
     if (this.mode_ == ScrollBar.Mode.VERTICAL) {
@@ skipping 26 matching lines @@
 
   this.button_.addEventListener('mousedown',
                                 this.onButtonPressed_.bind(this));
   window.addEventListener('mouseup', this.onMouseUp_.bind(this));
   window.addEventListener('mousemove', this.onMouseMove_.bind(this));
 };
 
 /**
  * Initialize a scrollbar.
  *
- * @param {Element} parent Parent element, must have a relative or absolute
+ * @param {Element} parent Parent node, must have a relative or absolute

[hirono, 2014/10/16 07:24:47]

nit: Parent node -> Parent element

[fukino, 2014/10/16 07:43:43]

Done.

  *     positioning.
  * @param {Element=} opt_scrollableArea Element with scrollable contents.
  *     If not passed, then call attachToView manually when the scrollable
  *     element becomes available.
  */
 ScrollBar.prototype.initialize = function(parent, opt_scrollableArea) {
   parent.appendChild(this);
   if (opt_scrollableArea)
     this.attachToView(opt_scrollableArea);
 };
 
 /**
  * Attaches the scrollbar to a scrollable element and attaches handlers.
  * @param {Element} view Scrollable element.
  */
 ScrollBar.prototype.attachToView = function(view) {
   this.view_ = view;
   this.view_.addEventListener('scroll', this.onScroll_.bind(this));
   this.view_.addEventListener('relayout', this.onRelayout_.bind(this));
   this.domObserver_ = new MutationObserver(this.onDomChanged_.bind(this));
-  this.domObserver_.observe(this.view_, {subtree: true, attributes: true});
+  this.domObserver_.observe(
+      this.view_,
+      /** @type {MutationObserverInit} */ ({subtree: true, attributes: true}));
   this.onRelayout_();
 };
 
 /**
  * Scroll handler.
  * @private
  */
 ScrollBar.prototype.onScroll_ = function() {
   this.scrollTop_ = this.view_.scrollTop;
   this.redraw_();
@@ skipping 202 matching lines @@
   return this.scrollHeight_ - this.bottomMarginForPanel_;
 };
 
 /**
  * Sets the bottom margin height of the view for the transparent preview panel.
  * @param {number} margin Margin to be set in px.
  */
 MainPanelScrollBar.prototype.setBottomMarginForPanel = function(margin) {
   this.bottomMarginForPanel_ = margin;
 };