MD Bookmarks: Enable the delete button in the toolbar overlay

chrome/test/data/webui/md_bookmarks/toolbar_test.js

 // Copyright 2017 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-toolbar>', function() {
   var toolbar;
   var store;
+  var commandManager;
+
+  suiteSetup(function() {
+    chrome.bookmarkManagerPrivate.removeTrees = function() {};
+  });
 
   setup(function() {
     store = new bookmarks.TestStore({
       nodes: testTree(createFolder('1', [
         createItem('2'),
         createItem('3'),
       ])),
       selection: {
         items: new Set(),
         anchor: null,
       },
     });
     bookmarks.Store.instance_ = store;
 
     toolbar = document.createElement('bookmarks-toolbar');
     replaceBody(toolbar);
+
+    commandManager = new TestCommandManager();
+    document.body.appendChild(commandManager);
   });
 
   test('selecting multiple items shows toolbar overlay', function() {
     assertFalse(toolbar.showSelectionOverlay);
 
     store.data.selection.items = new Set(['2']);
     store.notifyObservers();
     assertFalse(toolbar.showSelectionOverlay);
 
     store.data.selection.items = new Set(['2', '3']);
     store.notifyObservers();
     assertTrue(toolbar.showSelectionOverlay);
   });
+
+  test('clicking overlay delete button triggers a delete command', function() {
+    store.data.selection.items = new Set(['2', '3']);
+    store.notifyObservers();
+
+    Polymer.dom.flush();
+    MockInteractions.tap(
+        toolbar.$$('cr-toolbar-selection-overlay').deleteButton);
+
+    commandManager.assertLastCommand(Command.DELETE, ['2', '3']);
+  });
 });