Prefix string16 with base:: in ui/.

ui/views/touchui/touch_editing_menu.h

 // Copyright (c) 2013 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.
 
 #ifndef UI_VIEWS_TOUCHUI_TOUCH_EDITING_MENU_H_
 #define UI_VIEWS_TOUCHUI_TOUCH_EDITING_MENU_H_
 
 #include "ui/gfx/point.h"
 #include "ui/views/bubble/bubble_delegate.h"
 #include "ui/views/controls/button/button.h"
@@ skipping 51 matching lines @@
   virtual void ButtonPressed(Button* sender, const ui::Event& event) OVERRIDE;
 
   // Overridden from BubbleDelegateView.
   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
 
   // Queries the |controller_| for what elements to show in the menu and sizes
   // the menu appropriately.
   void CreateButtons();
 
   // Helper method to create a single button.
-  Button* CreateButton(const string16& title, int tag);
+  Button* CreateButton(const base::string16& title, int tag);
 
   TouchEditingMenuController* controller_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchEditingMenuView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_TOUCHUI_TOUCH_SELECTION_CONTROLLER_IMPL_H_