Replace views::Event with ui::Event.

ui/views/examples/native_theme_button_example.cc

 // 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.
 
 #include "ui/views/examples/native_theme_button_example.h"
 
 #include <string>
 
 #include "base/logging.h"
 #include "base/stringprintf.h"
@@ skipping 233 matching lines @@
   column_set->AddColumn(GridLayout::FILL, GridLayout::FILL,
                         1, GridLayout::USE_PREF, 0, 0);
   column_set->AddPaddingColumn(0, 16);
   layout->StartRow(1, 1);
   layout->AddView(button_);
 
   layout->AddPaddingRow(0, 8);
 }
 
 void NativeThemeButtonExample::ButtonPressed(Button* sender,
-                                             const Event& event) {
+                                             const ui::Event& event) {
   PrintStatus(button_->MessWithState().c_str());
 }
 
 }  // namespace examples
 }  // namespace views