MD Settings: Set overscroll before attempting to scroll to section

chrome/browser/resources/settings/settings_main/settings_main.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.
 
 /**
  * @typedef {{about: boolean, basic: boolean, advanced: boolean}}
  */
 var MainPageVisibility;
 
 /**
@@ skipping 170 matching lines @@
             (!this.hasExpandedSection_ && this.advancedToggleExpanded_),
       };
 
       if (this.showPages_.advanced) {
         assert(!this.pageVisibility ||
             this.pageVisibility.advancedSettings !== false);
         this.advancedToggleExpanded_ = true;
       }
     }
 
-    // Wait for any other changes prior to calculating the overflow padding.
+    // Calculate the overflow padding.
+    this.setOverscroll_(this.overscrollHeight_());

[dschuyler, 2016/09/08 21:00:37]

I added some logging to see how often this call
has correct data (compared to the version called
after a timeout). It occasionally does have the 
correct value, such as when the net effect is 
scrolling down to a section. It will also get 
incorrect values, such as when the net effect is
scrolling up to a section.

Is there some way to chain the actions with a 
promise or events (avoiding timeouts or using
stale data)?

+
+    // Wait for any other changes, then calculate the overflow padding again.
     setTimeout(function() {
       // Ensure any dom-if reflects the current properties.
       Polymer.dom.flush();
 
       this.setOverscroll_(this.overscrollHeight_());
     }.bind(this));
   },
 
   /**
    * Return the height that the overscroll padding should be set to.
@@ skipping 108 matching lines @@
 
   /**
    * @param {(boolean|undefined)} visibility
    * @return {boolean} True unless visibility is false.
    * @private
    */
   showAdvancedSettings_: function(visibility) {
     return visibility !== false;
   },
 });