Make lists in the passwords section aware of the scroll target.

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 68 matching lines @@
     },
 
     /**
      * Dictionary defining page visibility.
      * @type {!GuestModePageVisibility}
      */
     pageVisibility: {
       type: Object,
       value: function() { return {}; },
     },
+
+    /**
+     * The scroll target for the lists in this section.
+     * @type {Element}
+     */
+    scrollTarget: HTMLElement,
   },
 
   /** @override */
   attached: function() {
     document.addEventListener('toggle-advanced-page', function(e) {
       this.advancedToggleExpanded_ = e.detail;
       this.updatePagesShown_();
     }.bind(this));
 
     var currentRoute = settings.getCurrentRoute();
@@ skipping 266 matching lines @@
 
   /**
    * @param {(boolean|undefined)} visibility
    * @return {boolean} True unless visibility is false.
    * @private
    */
   showAdvancedSettings_: function(visibility) {
     return visibility !== false;
   },
 });