Readd base::UnwrapTraits to support rvalue-reference wrappers

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 361 matching lines @@
         'android/library_loader/library_prefetcher_unittest.cc',
         'android/path_utils_unittest.cc',
         'android/scoped_java_ref_unittest.cc',
         'android/sys_utils_unittest.cc',
         'at_exit_unittest.cc',
         'atomicops_unittest.cc',
         'barrier_closure_unittest.cc',
         'base64_unittest.cc',
         'base64url_unittest.cc',
         'big_endian_unittest.cc',
+        'bind_helpers_unittest.cc',
         'bind_unittest.cc',
         'bind_unittest.nc',
         'bit_cast_unittest.cc',
         'bits_unittest.cc',
         'build_time_unittest.cc',
         'callback_helpers_unittest.cc',
         'callback_list_unittest.cc',
         'callback_list_unittest.nc',
         'callback_unittest.cc',
         'callback_unittest.nc',
@@ skipping 1409 matching lines @@
                 ['include', 'mac/bind_objc_block_unittest_arc\\.mm$'],
                 ['include', 'mac/scoped_nsobject_unittest_arc\\.mm$'],
               ],
             }]
           ],
         },
       ],
     }],
   ],
 }