[MD Bookmarks] Make disabled buttons in context menu do nothing when clicked.

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

Index: chrome/test/data/webui/md_bookmarks/command_manager_test.js
diff --git a/chrome/test/data/webui/md_bookmarks/command_manager_test.js b/chrome/test/data/webui/md_bookmarks/command_manager_test.js
index 47c55630ee3b02db4b10b42e3e660961048434c0..9f745489cf7891c7469573fd4312a760593fa3ae 100644
--- a/chrome/test/data/webui/md_bookmarks/command_manager_test.js
+++ b/chrome/test/data/webui/md_bookmarks/command_manager_test.js
@@ -259,6 +259,13 @@ suite('<bookmarks-command-manager>', function() {
     commandManager.root.querySelectorAll('hr').forEach(element => {
       assertTrue(element.hidden);
     });
+
+    var commandItem = {};

[tsergeant, 2017/06/28 04:42:06]

I think this is the slightly wrong place to put this check.

In this test, prefs.canEdit == false, so the edit and delete options will be
entirely hidden, not just disabled.

The next test below tests the case you're after, where the buttons will be
disabled but not hidden.

[calamity, 2017/06/28 04:55:06]

Done.

+    commandManager.root.querySelectorAll('.dropdown-item').forEach(element => {
+      commandItem[element.getAttribute('command')] = element;
+    });
+    MockInteractions.tap(commandItem[Command.EDIT]);
+    commandManager.assertLastCommand(null);
   });
 
   test('cannot edit unmodifiable nodes', function() {