Make sure the PDF material toolbar gets hidden after loading.

chrome/browser/resources/pdf/ui_manager.js

 // Copyright 2015 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';
 
 var HIDE_TIMEOUT = 2000;
 
 /**
  * Creates a UI Manager to handle transitioning of toolbars and panes.
  * @constructor
  * @param {Object} window The window containing the UI.
  * @param {Object} toolbar The toolbar element.
  * @param {Array} panes The panes that may be pulled in.
  */
 function UiManager(window, toolbar, panes) {
   this.window_ = window;
   this.toolbar_ = toolbar;
   this.panes_ = panes;
 
   this.uiTimeout_ = null;
 
   var userInputs = ['click', 'keydown', 'mousemove', 'scroll'];
   for (var i = 0; i < userInputs.length; i++)
-    this.window_.addEventListener(userInputs[i], this.showUi_.bind(this));
+    this.window_.addEventListener(userInputs[i], this.showUi.bind(this));
 }
 
 UiManager.prototype = {
   /**
    * @private
    * Display the toolbar and any pane that was previously opened.
    */
-  showUi_: function() {
+  showUi: function() {
     this.toolbar_.show();
     for (var i = 0; i < this.panes_.length; i++)
       this.panes_[i].showIfOpenedByUser();
 
     if (this.uiTimeout_)
       clearTimeout(this.uiTimeout_);
     this.uiTimeout_ = setTimeout(this.hideUi_.bind(this), HIDE_TIMEOUT);
   },
 
   /**
    * @private
    * Hide the toolbar and any pane that was previously opened.
    */
   hideUi_: function() {
     this.toolbar_.hide();
     for (var i = 0; i < this.panes_.length; i++)
       this.panes_[i].hideIfOpenedByUser();
   }
 };