Add views::Button style enum for LabelButton [native] styling, etc.

ui/views/controls/button/custom_button.h

Index: ui/views/controls/button/custom_button.h
diff --git a/ui/views/controls/button/custom_button.h b/ui/views/controls/button/custom_button.h
index bb3a6a27340efcc63b109ad0f99659c5ea406ec4..c44d3c8df2fb04b119d913e94e078f459c6cda32 100644
--- a/ui/views/controls/button/custom_button.h
+++ b/ui/views/controls/button/custom_button.h
@@ -31,15 +31,6 @@ class VIEWS_EXPORT CustomButton : public Button,
 
   virtual ~CustomButton();
 
-  // Possible states
-  enum ButtonState {
-    STATE_NORMAL = 0,
-    STATE_HOVERED,
-    STATE_PRESSED,
-    STATE_DISABLED,
-    STATE_COUNT
-  };
-
   // Get/sets the current display state of the button.
   ButtonState state() const { return state_; }
   void SetState(ButtonState state);
@@ -158,7 +149,7 @@ class VIEWS_EXPORT CustomButton : public Button,
 class VIEWS_EXPORT CustomButtonStateChangedDelegate {
 public:
   virtual ~CustomButtonStateChangedDelegate() {}
-  virtual void StateChanged(CustomButton::ButtonState state) = 0;
+  virtual void StateChanged(Button::ButtonState state) = 0;
 
 protected:
   CustomButtonStateChangedDelegate() {}