Create LibDispatchTaskRunner, a SingleThreadTaskRunner that is backed by a libdispatch queue.

base/base.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,
   },
   'includes': [
     '../build/win_precompile.gypi',
@@ skipping 446 matching lines @@
         'json/json_parser_unittest.cc',
         'json/json_reader_unittest.cc',
         'json/json_value_converter_unittest.cc',
         'json/json_value_serializer_unittest.cc',
         'json/json_writer_unittest.cc',
         'json/string_escape_unittest.cc',
         'lazy_instance_unittest.cc',
         'logging_unittest.cc',
         'mac/bind_objc_block_unittest.mm',
         'mac/foundation_util_unittest.mm',
+        'mac/libdispatch_task_runner_unittest.cc',
         'mac/mac_util_unittest.mm',
         'mac/objc_property_releaser_unittest.mm',
         'mac/scoped_sending_event_unittest.mm',
         'md5_unittest.cc',
         'memory/aligned_memory_unittest.cc',
         'memory/linked_ptr_unittest.cc',
         'memory/ref_counted_memory_unittest.cc',
         'memory/ref_counted_unittest.cc',
         'memory/scoped_nsobject_unittest.mm',
         'memory/scoped_ptr_unittest.cc',
@@ skipping 622 matching lines @@
             'base_unittests.isolate',
           ],
           'sources': [
             'base_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }