Make chrome/ be documentElement/body agnostic with regards to scrollTop/Left

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.
@@ skipping 97 matching lines @@
       }
       return null;
     },
 
     /**
      * Freezes current page, makes it impossible to scroll it.
      * @param {boolean} freeze True if the page should be frozen.
      * @private
      */
     freeze_: function(freeze) {
+      var scrollTop = scrollTopForDocument(document);
+      var scrollLeft = scrollLeftForDocument(document);
+
       if (freeze) {
-        this.lastScrollTop = document.documentElement.scrollTop;
+        this.lastScrollTop = scrollTop;

[Dan Beam, 2013/11/13 23:31:07]

nit: replace `var scrollTop = ...;` with:

  this.lastScrollTop = scrollTopForDocument(document);

so it's only requested when if (freeze) is true.

         document.body.style.overflow = 'hidden';
-        window.scroll(document.documentElement.scrollLeft, 0);
+        window.scroll(scrollLeft, 0);
       } else {
         document.body.style.overflow = 'auto';
-        window.scroll(document.documentElement.scrollLeft, this.lastScrollTop);
+        window.scroll(scrollLeft, this.lastScrollTop);
       }
     },
 
     /**
      * Initializes current page.
      * @param {string} name Name of the current page.
      */
     initialize: function(name) {
       this.name = name;
       this.pageDiv = $(name);
@@ skipping 101 matching lines @@
           return;
       }
     },
   };
 
   // Export
   return {
     HelpBasePage: HelpBasePage
   };
 });