MD History: Delete button in the toolbar allows deletion of multiple history-items.

chrome/browser/resources/md_history/history_item.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.
 
 Polymer({
   is: 'history-item',
 
   properties: {
     timeAccessed_: {
       type: String,
@@ skipping 72 matching lines @@
     var position = this.$['menu-button'].getBoundingClientRect();
 
     this.fire('toggle-menu', {
       x: position.left,
       y: position.top,
       accessTime: this.timestamp_
     });
 
     // Stops the 'tap' event from closing the menu when it opens.
     e.stopPropagation();
+  },
+
+  selectionNotAllowed_: function() {
+    return !loadTimeData.getBoolean('allowDeletingHistory');
   }
 });