Typecheck chrome://help using CompilerPass.java, everything except dependency to options

chrome/browser/resources/help/help_base_page.js

 // Copyright 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.
 
 // Helper base class for all help pages and overlays, which controls
 // overlays, focus and scroll. This class is partially based on
 // OptionsPage, but simpler and contains only overlay- and focus-
 // handling logic. As in OptionsPage each page can be an overlay itself,
 // but each page contains its own list of registered overlays which can be
 // displayed over it.
 //
 // TODO (ygorshenin@): crbug.com/313244.
 cr.define('help', function() {
+  /**
+   * @constructor
+   * @extends {HTMLDivElement}
+   */
   function HelpBasePage() {
   }
 
   HelpBasePage.prototype = {
     __proto__: HTMLDivElement.prototype,
 
     /**
      * name of the page, should be the same as an id of the
      * corresponding HTMLDivElement.
      */
@@ skipping 119 matching lines @@
     /**
      * @return {HTMLDivElement} Topmost visible page, or null, if
      * there are no visible pages.
      */
     getTopmostVisiblePage: function() {
       return this.getVisibleOverlay_() || this.getVisibleNonOverlay_();
     },
 
     /**
      * Registers overlay.
-     * @param {HelpBasePage} overlay Overlay that should be registered.
+     * @param {help.HelpBasePage} overlay Overlay that should be registered.
      */
     registerOverlay: function(overlay) {
       this.registeredOverlays[overlay.name] = overlay;
       overlay.isOverlay = true;
     },
 
     /**
      * Shows or hides current page.
      * @param {boolean} visible True if current page should be displayed.
      */
@@ skipping 26 matching lines @@
       return !this.pageDiv.hidden;
     },
 
     /**
      * This method returns overlay container, it should be called only
      * on overlays.
      * @return {HTMLDivElement} overlay container.
      */
     get container() {
       assert(this.isOverlay);
-      return this.pageDiv.parentNode;
+      return /** @type {HTMLDivElement} */(this.pageDiv.parentNode);

[Dan Beam, 2014/08/05 18:49:27]

why don't you make this HTMLElement instead?  Div is pretty specific and offers
no benefits, afaik.

[Vitaly Pavlenko, 2014/08/05 23:00:54]

Done.

     },
 
     /**
      * Shows registered overlay.
      * @param {string} name Name of registered overlay to show.
      */
     showOverlay: function(name) {
       var currentPage = this.getTopmostVisiblePage();
       currentPage.storeLastFocusedElement_();
       currentPage.freeze_(true);
@@ skipping 34 matching lines @@
           return;
       }
     },
   };
 
   // Export
   return {
     HelpBasePage: HelpBasePage
   };
 });