MD Settings: Workaround for section expand/collapse animation jank.

chrome/browser/resources/settings/settings_page/main_page_behavior.js

 // Copyright 2016 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.
 
 // Fast out, slow in.
 var EASING_FUNCTION = 'cubic-bezier(0.4, 0, 0.2, 1)';
 var EXPAND_DURATION = 350;
 
 /**
  * Provides animations to expand and collapse individual sections in a page.
@@ skipping 342 matching lines @@
       var element = this.getSection_(this.currentRoute.section);
       if (!element)
         return;
 
       var host = findAncestor(element, function(n) { return n.host; }).host;
       if (host.scrollHeight == 0) {
         setTimeout(pollForScrollHeight.bind(this), 100);
         return;
       }
 
-      element.scrollIntoView();
+      // TODO(michaelpg): due to the workaround for crbug.com/617827 in
+      // settings_page_css.html, we have to use element.offsetTop instead of
+      // relying on element.scrollIntoView() so the margin is included.
+      host.scroller.scrollTop = element.offsetTop;
     }.bind(this));
   },
 
   /** @private */
   currentRouteChanged_: function(newRoute, oldRoute) {
     var newRouteIsSubpage = newRoute && newRoute.subpage.length;
     var oldRouteIsSubpage = oldRoute && oldRoute.subpage.length;
 
     if (!oldRoute && newRouteIsSubpage) {
       // Allow the page to load before expanding the section. TODO(michaelpg):
@@ skipping 31 matching lines @@
         this.$$('[section=' + section + ']'));
   },
 };
 
 
 /** @polymerBehavior */
 var RoutableBehavior = [
   MainPageBehavior,
   RoutableBehaviorImpl
 ];