Fix obsolete dependencies so that needless recompilation does not happen.

content/content_common.gypi

 # Copyright (c) 2011 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.
 
 {
   'targets': [
     {
       'target_name': 'content_common',
       'type': 'static_library',
       'dependencies': [
@@ skipping 146 matching lines @@
         'common/navigation_types.h',
         'common/notification_details.cc',
         'common/notification_details.h',
         'common/notification_observer.h',
         'common/notification_registrar.cc',
         'common/notification_registrar.h',
         'common/notification_service.cc',
         'common/notification_service.h',
         'common/notification_source.cc',
         'common/notification_source.h',
-        'common/notification_type.h',
         'common/p2p_messages.h',
         'common/p2p_sockets.h',
         'common/page_transition_types.cc',
         'common/page_transition_types.h',
         'common/page_type.h',
         'common/page_zoom.h',
         'common/pepper_file_messages.cc',
         'common/pepper_file_messages.h',
         'common/pepper_messages.cc',
         'common/pepper_messages.h',
@@ skipping 164 matching lines @@
           ],
           'sources': [
             'common/gpu/media/omx_video_decode_accelerator_unittest.cc',
           ],
         }
       ],
     },
    ],
   ],
 }