Change the print preview UI to use the material design style buttons for zoom

chrome/browser/resources/pdf/toolbar_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';
 
 /** Idle time in ms before the UI is hidden. */
 var HIDE_TIMEOUT = 2000;
 /** Time in ms after force hide before toolbar is shown again. */
 var FORCE_HIDE_TIMEOUT = 1000;
@@ skipping 50 matching lines @@
   this.sideToolbarAllowedOnly_ = false;
   this.sideToolbarAllowedOnlyTimer_ = null;
 
   this.window_.addEventListener('resize', this.resizeDropdowns_.bind(this));
   this.resizeDropdowns_();
 }
 
 ToolbarManager.prototype = {
 
   showToolbarsForMouseMove: function(e) {
-    this.isMouseNearTopToolbar_ = isMouseNearTopToolbar(e);
+    this.isMouseNearTopToolbar_ = this.toolbar_ && isMouseNearTopToolbar(e);
     this.isMouseNearSideToolbar_ = isMouseNearSideToolbar(e);
 
     // Allow the top toolbar to be shown if the mouse moves away from the side
     // toolbar (as long as the timeout has elapsed).
     if (!this.isMouseNearSideToolbar_ && !this.sideToolbarAllowedOnlyTimer_)
       this.sideToolbarAllowedOnly_ = false;
 
     // Allow the top toolbar to be shown if the mouse moves to the top edge.
     if (this.isMouseNearTopToolbar_)
       this.sideToolbarAllowedOnly_ = false;
 
     // Show the toolbars if the mouse is near the top or right of the screen or
     // if the mouse moved fast.
     if (this.isMouseNearTopToolbar_ || this.isMouseNearSideToolbar_ ||
         isHighVelocityMouseMove(e)) {
       if (this.sideToolbarAllowedOnly_)
         this.zoomToolbar_.show();
       else
         this.showToolbars();
     }
     this.hideToolbarsAfterTimeout();
   },
 
   /**
    * Display both UI toolbars.
    */
   showToolbars: function() {
-    this.toolbar_.show();
+    if (this.toolbar_)
+      this.toolbar_.show();
     this.zoomToolbar_.show();
   },
 
   /**
    * Check if the toolbars are able to be closed, and close them if they are.
    * Toolbars may be kept open based on mouse/keyboard activity and active
    * elements.
    */
   hideToolbarsIfAllowed: function() {
-    if (!(this.isMouseNearTopToolbar_ || this.isMouseNearSideToolbar_ ||
-        this.toolbar_.shouldKeepOpen())) {
+    if (this.isMouseNearSideToolbar_ || this.isMouseNearTopToolbar_)
+      return;
+
+    if (this.toolbar_ && this.toolbar_.shouldKeepOpen())
+      return;
+
+    if (this.toolbar_)
       this.toolbar_.hide();
-      this.zoomToolbar_.hide();
-    }
+    this.zoomToolbar_.hide();
   },
 
   /**
    * Hide the toolbar after the HIDE_TIMEOUT has elapsed.
    */
   hideToolbarsAfterTimeout: function() {
     if (this.toolbarTimeout_)
       clearTimeout(this.toolbarTimeout_);
     this.toolbarTimeout_ =
         setTimeout(this.hideToolbarsIfAllowed.bind(this), HIDE_TIMEOUT);
   },
 
   /**
    * Hide the 'topmost' layer of toolbars. Hides any dropdowns that are open, or
    * hides the basic toolbars otherwise.
    */
   hideSingleToolbarLayer: function() {
-    if (!this.toolbar_.hideDropdowns())
+    if (!this.toolbar_ || !this.toolbar_.hideDropdowns())
       this.hideToolbarsIfAllowed();
   },
 
   /**
    * Hide the top toolbar and keep it hidden until both:
    * - The mouse is moved away from the right side of the screen
    * - 1 second has passed.
    *
    * The top toolbar can be immediately re-opened by moving the mouse to the top
    * of the screen.
    */
   forceHideTopToolbar: function() {
+    if (!this.toolbar_)
+      return;
     this.toolbar_.hide();
     this.sideToolbarAllowedOnly_ = true;
     this.sideToolbarAllowedOnlyTimer_ = this.window_.setTimeout(function() {
       this.sideToolbarAllowedOnlyTimer_ = null;
     }.bind(this), FORCE_HIDE_TIMEOUT);
   },
 
   /**
    * Updates the size of toolbar dropdowns based on the positions of the rest of
    * the UI.
    * @private
    */
   resizeDropdowns_: function() {
+    if (!this.toolbar_)
+      return;
     var lowerBound = this.window_.innerHeight - this.zoomToolbar_.clientHeight;
     this.toolbar_.setDropdownLowerBound(lowerBound);
   }
 };