Cleans up gyp file for views example and removes duplicate code

ui/views/examples/menu_example.h

 // Copyright (c) 2012 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_EXAMPLES_MENU_EXAMPLE_H_
 #define UI_VIEWS_EXAMPLES_MENU_EXAMPLE_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/views/examples/example_base.h"
 
 namespace views {
 namespace examples {
 
 // MenuExample demonstrates how to use the MenuModelAdapter and MenuRunner
 // classes.
-class MenuExample : public ExampleBase {
+class VIEWS_EXAMPLES_EXPORT MenuExample : public ExampleBase {
  public:
   MenuExample();
   virtual ~MenuExample();
 
   // Overridden from ExampleBase:
   virtual void CreateExampleView(View* container) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MenuExample);
 };
 
 }  // namespace examples
 }  // namespace views
 
 #endif  // UI_VIEWS_EXAMPLES_MENU_EXAMPLE_H_