[MD Bookmarks] Deselect items when clicking outside the bookmark card.

chrome/test/data/webui/md_bookmarks/list_test.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.
 
 suite('<bookmarks-list>', function() {
   var list;
   var store;
 
   setup(function() {
     store = new bookmarks.TestStore({
@@ skipping 62 matching lines @@
     assertDeepEquals(['1'], store.lastAction.items);
 
     // Anchor item doesn't exist:
     store.data.selection.anchor = '42';
 
     customClick(items[1], {shiftKey: true});
 
     assertEquals('3', store.lastAction.anchor);
     assertDeepEquals(['3'], store.lastAction.items);
   });
+
+  test('deselects items on click outside of card', function() {
+    customClick(list);
+    assertEquals('deselect-items', store.lastAction.name);
+  });
 });