Move DBMessageFilter to content/child since its only used in child ptypes

content/content_common.gypi

 # 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.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../components/tracing.gyp:tracing',
     '../media/media.gyp:media',
     '../net/net.gyp:net',
@@ skipping 131 matching lines @@
     'common/content_ipc_logging.cc',
     'common/content_message_generator.cc',
     'common/content_message_generator.h',
     'common/content_param_traits.cc',
     'common/content_param_traits.h',
     'common/content_param_traits_macros.h',
     'common/content_paths.cc',
     'common/cookie_data.cc',
     'common/cookie_data.h',
     'common/database_messages.h',
-    'common/db_message_filter.cc',
-    'common/db_message_filter.h',
     'common/desktop_notification_messages.h',
     'common/device_motion_messages.h',
     'common/device_orientation_messages.h',
     'common/devtools_messages.h',
     'common/dom_storage_messages.h',
     'common/drag_event_source_info.h',
     'common/drag_messages.h',
     'common/drag_traits.h',
     'common/edit_command.h',
     'common/file_utilities_messages.h',
@@ skipping 378 matching lines @@
         '..\\third_party\\directxsdk\\files\\Redist\\<(input)',
         '<(output)',
         '<(PRODUCT_DIR)',
         ],
         'msvs_cygwin_shell': 1,
       },
      ]
     }],
   ],
 }