platform-window: Add a PlatformWindowFactory for creating windows.

ui/platform_window/platform_window.gyp

 # Copyright 2014 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': [{
+    'target_name': 'platform_window_types',
+    'type': '<(component)',
+    'sources': [
+      'types/platform_window.h',
+      'types/platform_window_delegate.h',
+    ],
+  }, {
     'target_name': 'platform_window',
     'type': '<(component)',
+    'dependencies': [
+      '../../base/base.gyp:base',
+      '../events/platform/events_platform.gyp:events_platform',
+      'platform_window_types',
+    ],
     'defines': [ 'PLATFORM_WINDOW_IMPLEMENTATION' ],
     'sources': [
-      'platform_window.h',
-      'platform_window_delegate.h',
       'platform_window_export.h',
+      'platform_window_factory.cc',
+      'platform_window_factory.h',
+    ],
+    'conditions': [
+      ['OS=="win"', {
+        'dependencies': [
+          '../gfx/gfx.gyp:gfx',
+          'win/win_window.gyp:win_window',
+        ],
+      }],
+      ['use_x11==1', {
+        'dependencies': [ 'x11/x11_window.gyp:x11_window', ],
+      }],
+      ['use_ozone==1', {
+        'dependencies': [ '../ozone/ozone.gyp:ozone', ],
+      }],
     ],
   }],
 }