Cleans up gyp file for views example and removes duplicate code

ui/views/examples/button_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_BUTTON_EXAMPLE_H_
 #define UI_VIEWS_EXAMPLES_BUTTON_EXAMPLE_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/views/controls/button/text_button.h"
 #include "ui/views/examples/example_base.h"
 
 namespace views {
 
 class ImageButton;
 class LabelButton;
 
 namespace examples {
 
 // ButtonExample simply counts the number of clicks.
-class ButtonExample : public ExampleBase, public ButtonListener {
+class VIEWS_EXAMPLES_EXPORT ButtonExample : public ExampleBase,
+                                            public ButtonListener {
  public:
   ButtonExample();
   virtual ~ButtonExample();
 
   // Overridden from ExampleBase:
   virtual void CreateExampleView(View* container) OVERRIDE;
 
  private:
   void TextButtonPressed(const ui::Event& event);
   void LabelButtonPressed(const ui::Event& event);
@@ skipping 14 matching lines @@
   // The number of times the buttons are pressed.
   int count_;
 
   DISALLOW_COPY_AND_ASSIGN(ButtonExample);
 };
 
 }  // namespace examples
 }  // namespace views
 
 #endif  // UI_VIEWS_EXAMPLES_BUTTON_EXAMPLE_H_