aura: Use PlatformWindow from WindowTreeHost.

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 106 matching lines @@
           'dependencies': [
             '../../build/linux/system.gyp:x11',
             '../../build/linux/system.gyp:xrandr',
             '../../build/linux/system.gyp:xi',
             '../events/platform/x11/x11_events_platform.gyp:x11_events_platform',
           ],
         }],
         ['OS=="win"', {
           'dependencies': [
             '../metro_viewer/metro_viewer.gyp:metro_viewer_messages',
+            '../platform_window/win/win_window.gyp:win_window',
             '../../ipc/ipc.gyp:ipc',
           ],
           'sources!': [
             'input_state_lookup.cc',
           ],
         }],
         ['use_ozone==1', {
           'dependencies': [
             '../events/ozone/events_ozone.gyp:events_ozone',
             '../ozone/ozone.gyp:ozone',
@@ skipping 162 matching lines @@
         ['OS=="linux" and use_allocator!="none"', {
           'dependencies': [
            # See http://crbug.com/162998#c4 for why this is needed.
             '../../base/allocator/allocator.gyp:allocator',
           ],
         }],
       ],
     },
   ],
 }