Replace views::Event with ui::Event.

ui/views/controls/button/button.h

Index: ui/views/controls/button/button.h
===================================================================
--- ui/views/controls/button/button.h	(revision 151055)
+++ ui/views/controls/button/button.h	(working copy)
@@ -16,7 +16,7 @@
 // pressed.
 class VIEWS_EXPORT ButtonListener {
  public:
-  virtual void ButtonPressed(Button* sender, const views::Event& event) = 0;
+  virtual void ButtonPressed(Button* sender, const ui::Event& event) = 0;
 
  protected:
   virtual ~ButtonListener() {}
@@ -50,7 +50,7 @@
   explicit Button(ButtonListener* listener);
 
   // Cause the button to notify the listener that a click occurred.
-  virtual void NotifyClick(const views::Event& event);
+  virtual void NotifyClick(const ui::Event& event);
 
   // The button's listener. Notified when clicked.
   ButtonListener* listener_;