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

content/content_child.gypi

 # Copyright 2013 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',
     '../ui/ui.gyp:ui',
     '../url/url.gyp:url_lib',
@@ skipping 15 matching lines @@
     'child/child_histogram_message_filter.cc',
     'child/child_histogram_message_filter.h',
     'child/child_process.cc',
     'child/child_process.h',
     'child/child_resource_message_filter.cc',
     'child/child_resource_message_filter.h',
     'child/child_thread.cc',
     'child/child_thread.h',
     'child/database_util.cc',
     'child/database_util.h',
+    'child/db_message_filter.cc',
+    'child/db_message_filter.h',
     'child/fileapi/file_system_dispatcher.cc',
     'child/fileapi/file_system_dispatcher.h',
     'child/fileapi/webfilesystem_callback_adapters.cc',
     'child/fileapi/webfilesystem_callback_adapters.h',
     'child/fileapi/webfilesystem_impl.cc',
     'child/fileapi/webfilesystem_impl.h',
     'child/fileapi/webfilewriter_impl.cc',
     'child/fileapi/webfilewriter_impl.h',
     'child/image_decoder.cc',
     'child/image_decoder.h',
@@ skipping 59 matching lines @@
     }, {  # OS!="ios"
       'dependencies': [
         '../third_party/WebKit/public/blink.gyp:blink',
         '../third_party/npapi/npapi.gyp:npapi',
         '../webkit/common/webkit_common.gyp:webkit_common',
         '../webkit/support/webkit_support.gyp:glue_child',
       ],
     }],
   ],
 }