Use sequenced workers for the getting the system's font list.

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',
     '../build/temp_gyp/googleurl.gyp:googleurl',
     '../components/tracing.gyp:tracing',
     '../media/media.gyp:media',
@@ skipping 174 matching lines @@
     'common/fileapi/webfilesystem_impl.h',
     'common/fileapi/webfilewriter_impl.cc',
     'common/fileapi/webfilewriter_impl.h',
     'common/file_utilities_messages.h',
     'common/find_match_rect_android.cc',
     'common/find_match_rect_android.h',
     'common/font_cache_dispatcher_win.cc',
     'common/font_cache_dispatcher_win.h',
     'common/font_config_ipc_linux.cc',
     'common/font_config_ipc_linux.h',
+    'common/font_list.cc',
     'common/font_list.h',
     'common/font_list_android.cc',
     'common/font_list_linux.cc',
     'common/font_list_mac.mm',
     'common/font_list_win.cc',
     'common/gamepad_hardware_buffer.h',
     'common/gamepad_messages.h',
     'common/gamepad_seqlock.cc',
     'common/gamepad_seqlock.h',
     'common/gamepad_user_gesture.cc',
@@ skipping 378 matching lines @@
         '..\\third_party\\directxsdk\\files\\Redist\\<(input)',
         '<(output)',
         '<(PRODUCT_DIR)',
         ],
         'msvs_cygwin_shell': 1,
       },
      ]
     }],
   ],
 }