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

chrome/browser/resources/md_history/history_toolbar.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-toolbar',
   properties: {
     // Number of history items currently selected.
     count: {
       type: Number,
@@ skipping 13 matching lines @@
    * Changes the toolbar background color depending on whether any history items
    * are currently selected.
    * @private
    */
   changeToolbarView_: function() {
     this.itemsSelected_ = this.count != 0;
   },
 
   onClearSelectionTap_: function() {
     this.fire('unselect-all');
+  },
+
+  onDeleteTap_: function() {
+    this.fire('delete-selected');
+  },
+
+  /**
+   * If the user is a supervised user the delete button is not shown.
+   * @private
+   */
+  deletingAllowed_: function() {
+    return loadTimeData.getBoolean('allowDeletingHistory');
   }
 });