Convert Aura to use ui::Event.

ui/aura/aura.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 59 matching lines @@
         'desktop/desktop_stacking_client.cc',
         'desktop/desktop_stacking_client.h',
         'dispatcher_linux.cc',
         'dispatcher_linux.h',
         'dispatcher_win.cc',
         'display_observer.cc',
         'display_observer.h',
         'env.cc',
         'env.h',
         'env_observer.h',
-        'event.cc',
-        'event.h',
         'event_filter.h',
-        'event_mac.mm',
-        'event_mac.h',
         'focus_change_observer.h',
         'focus_manager.cc',
         'focus_manager.h',
         'layout_manager.cc',
         'layout_manager.h',
         'display_change_observer_x11.cc',
         'display_change_observer_x11.h',
         'display_manager.cc',
         'display_manager.h',
         'root_window_host.h',
@@ skipping 179 matching lines @@
       ],
       'sources': [
         'gestures/gesture_recognizer_unittest.cc',
         'test/run_all_unittests.cc',
         'test/test_suite.cc',
         'test/test_suite.h',
         'root_window_unittest.cc',
         'shared/compound_event_filter_unittest.cc',
         'shared/input_method_event_filter_unittest.cc',
         'event_filter_unittest.cc',
-        'event_unittest.cc',
         'window_unittest.cc',
       ],
       'conditions': [
         # osmesa GL implementation is used on linux.
         ['OS=="linux"', {
           'dependencies': [
             '<(DEPTH)/third_party/mesa/mesa.gyp:osmesa',
           ],
         }],
       ],
     },
   ],
 }