Make MessageCenter a singleton object and build on Windows.

ui/views/views.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,
   },
   'target_defaults': {
     'conditions': [
       ['use_aura==1', {
@@ skipping 472 matching lines @@
               ],
             }],
           ],
         }],
         ['use_aura==0', {
           'sources/': [
             ['exclude', 'corewm'],
             ['exclude', 'widget/desktop_aura'],
           ],
           'sources!': [
-            'bubble/tray_bubble_view.cc',
-            'bubble/tray_bubble_view.h',
             'widget/native_widget_aura_window_observer.cc',
             'widget/native_widget_aura_window_observer.h',
             'widget/widget_aura_utils.cc',
             'widget/widget_aura_utils.h',
           ],
         }],
         ['chromeos==1', {
           'sources/': [
             ['exclude', 'widget/desktop_aura'],
           ],
@@ skipping 481 matching lines @@
           'sources/': [
             # This is needed because the aura rule strips it from the default
             # sources list.
             ['include', '^../../content/app/startup_helper_win.cc'],
           ],
         }],
       ],
     },  # target_name: views_examples_with_content_exe
   ],
 }