[MD Bookmarks] Add edit folder.

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 TEST_LIST =
+      [createItem('0'), createItem('1'), createFolder('2', [], null)];
+
+  setup(function() {
+    list = document.createElement('bookmarks-list');
+    replaceBody(list);
+    list.displayedList = TEST_LIST;
+  });
+
+  test('folder menu item hides the url field', function() {
+    // Bookmark editor shows the url field.
+    list.menuItem_ = TEST_LIST[0];
+    assertFalse(list.$['url'].hidden);
+
+    // Folder editor hides the url field.
+    list.menuItem_ = TEST_LIST[2];
+    assertTrue(list.$['url'].hidden);
+  });
+
+  test('saving edit passes correct details to the update', function() {
+    // Saving bookmark edit.
+    var menuItem = TEST_LIST[0];
+    chrome.bookmarks.update = function(id, edit) {
+      assertEquals(menuItem.id, id);
+      assertEquals(menuItem.url, edit.url);
+      assertEquals(menuItem.title, edit.title);
+    };
+    list.menuItem_ = menuItem;
+    list.$.editBookmark.showModal();
+    list.onSaveEditTap_();
+
+    // Saving folder rename.
+    menuItem = TEST_LIST[2];
+    chrome.bookmarks.update = function(id, edit) {
+      assertEquals(menuItem.id, id);
+      assertEquals(menuItem.title, edit.title);
+      assertEquals(undefined, edit.url);
+    };
+    list.menuItem_ = menuItem;
+    list.$.editBookmark.showModal();
+    list.onSaveEditTap_();

[calamity, 2017/02/03 03:45:24]

If you're gonna open the actual dialog, seems a shame to not actually
MockInteractions.tap('#save-button')

[angelayang, 2017/02/06 00:49:39]

Sounds good

+  });
+});