MD History: Fix loading of history results in background tabs

chrome/browser/resources/md_history/list_container.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.
 
 Polymer({
   is: 'history-list-container',
 
   properties: {
     // The path of the currently selected page.
     selectedPage_: String,
@@ skipping 83 matching lines @@
 
   historyDeleted: function() {
     // Do not reload the list when there are items checked.
     if (this.getSelectedItemCount() > 0)
       return;
 
     // Reload the list with current search state.
     this.queryHistory(false);
   },
 
-  /** @return {HTMLElement} */
+  /** @return {Element} */
   getContentScrollTarget: function() {
     return this.getSelectedList_();
   },
 
   /** @return {number} */
   getSelectedItemCount: function() {
     return this.getSelectedList_().selectedPaths.size;
   },
 
   unselectAllItems: function(count) {
@@ skipping 161 matching lines @@
           if (index <= UMA_MAX_SUBSET_BUCKET_VALUE) {
             browserService.recordHistogram(
                 'HistoryPage.RemoveEntryPositionSubset', index,
                 UMA_MAX_SUBSET_BUCKET_VALUE);
           }
         }.bind(this));
     menu.closeMenu();
   },
 
   /**
-   * @return {HTMLElement}
+   * @return {Element}
    * @private
    */
-  getSelectedList_: function() { return this.$.content.selectedItem; },
+  getSelectedList_: function() { return this.$$('#' + this.selectedPage_); },
 
   /** @private */
   canDeleteHistory_: function() {
     return loadTimeData.getBoolean('allowDeletingHistory');
   }
 });