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,
       value: ''
@@ skipping 71 matching lines @@
   openMenu: function(e) {
     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();
+  },
+
+  selectionAllowed_: function() {

[tsergeant, 2016/01/25 01:43:15]

The truthiness of your variable/function names flip around a lot:

In the html:
disabled = selectionAllowed

In the js:
selectionAllowed = not allowDeletingHistory

If you think through it, you can figure out that it's correct. It's really
confusing to read, though, since something 'truthy' is being set to something
'falsey'.

Can you rename things to make this clearer?

[hsampson, 2016/01/25 04:15:42]

Done.

+    return !loadTimeData.getBoolean('allowDeletingHistory');
   }
 });