[MD History] Add URL parameter for search.

chrome/browser/resources/md_history/side_bar.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-side-bar',
 
   properties: {
     selectedPage: {
       type: String,
       notify: true
     },
+
+    route: Object,
   },
 
   /**
    * Handles menu selection changes.
    * @param {Event} e
    * @private
    */
   onSelect_: function(e) {
     this.fire('unselect-all');
   },
 
   /**
    * Returns the listbox menu item to select for the given page.
    * @param {string} selectedPage
    * @private
    */
   getSelection_(selectedPage) {
     if (selectedPage == 'grouped')
       return 'history';
 
     return selectedPage;
+  },
+
+  getQueryString_: function(route) {
+    return window.location.search;
   }
 });