[MD Bookmarks] Implement adding folders and bookmarks from toolbar menu.

chrome/browser/ui/webui/md_bookmarks/md_bookmarks_ui.cc

 // Copyright (c) 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.
 
 #include "chrome/browser/ui/webui/md_bookmarks/md_bookmarks_ui.h"
 
 #include <algorithm>
 
 #include "base/strings/string16.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 14 matching lines @@
   base::string16 str = l10n_util::GetStringUTF16(id);
   str.erase(std::remove(str.begin(), str.end(), '&'), str.end());
   source->AddString(message, str);
 }
 
 content::WebUIDataSource* CreateMdBookmarksUIHTMLSource(Profile* profile) {
   content::WebUIDataSource* source =
       content::WebUIDataSource::Create(chrome::kChromeUIBookmarksHost);
 
   // Localized strings (alphabetical order).
+  AddLocalizedString(source, "addBookmarkTitle",
+                     IDS_BOOKMARK_ADD_BOOKMARK_TITLE);
+  AddLocalizedString(source, "addFolderTitle",
+                     IDS_BOOKMARK_ADD_FOLDER_TITLE);
   AddLocalizedString(source, "cancelEdit", IDS_CANCEL);
   AddLocalizedString(source, "clearSearch",
                      IDS_MD_BOOKMARK_MANAGER_CLEAR_SEARCH);
   AddLocalizedString(source, "editBookmarkTitle", IDS_BOOKMARK_EDITOR_TITLE);
   AddLocalizedString(source, "editDialogNameInput",
                      IDS_BOOKMARK_MANAGER_NAME_INPUT_PLACE_HOLDER);
   AddLocalizedString(source, "editDialogUrlInput",
                              IDS_BOOKMARK_MANAGER_URL_INPUT_PLACE_HOLDER);
   AddLocalizedString(source, "emptyList",
                      IDS_MD_BOOKMARK_MANAGER_EMPTY_LIST);
@@ skipping 56 matching lines @@
   // Set up the chrome://bookmarks/ source.
   Profile* profile = Profile::FromWebUI(web_ui);
   content::WebUIDataSource::Add(profile,
                                 CreateMdBookmarksUIHTMLSource(profile));
 }
 
 // static
 bool MdBookmarksUI::IsEnabled() {
   return base::FeatureList::IsEnabled(features::kMaterialDesignBookmarks);
 }