[MD History] Disable menu button when history deletion is disabled.

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 261 matching lines @@
           }
         }.bind(this));
     menu.closeMenu();
   },
 
   /**
    * @return {HTMLElement}
    * @private
    */
   getSelectedList_: function() { return this.$.content.selectedItem; },
+
+  /** @private */
+  canDeleteHistory_: function() {
+    return loadTimeData.getBoolean('allowDeletingHistory');
+  }
 });