Cleans up gyp file for views example and removes duplicate code

ui/views/examples/bubble_example.h

 // Copyright (c) 2011 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_BUBBLE_EXAMPLE_H_
 #define UI_VIEWS_EXAMPLES_BUBBLE_EXAMPLE_H_
 
 #include "ui/views/controls/button/button.h"
 #include "ui/views/examples/example_base.h"
 
 namespace views {
 namespace examples {
 
 // A Bubble example.
-class BubbleExample : public ExampleBase, public ButtonListener {
+class VIEWS_EXAMPLES_EXPORT BubbleExample : public ExampleBase,
+                                            public ButtonListener {
  public:
   BubbleExample();
   virtual ~BubbleExample();
 
   // Overridden from ExampleBase.
   virtual void CreateExampleView(View* container) OVERRIDE;
 
  private:
   virtual void ButtonPressed(Button* sender, const ui::Event& event) OVERRIDE;
 
   Button* no_shadow_;
   Button* big_shadow_;
   Button* small_shadow_;
   Button* align_to_edge_;
   Button* persistent_;
   Button* fade_in_;
 
   DISALLOW_COPY_AND_ASSIGN(BubbleExample);
 };
 
 }  // namespace examples
 }  // namespace views
 
 #endif  // UI_VIEWS_EXAMPLES_BUBBLE_EXAMPLE_H_