Add base\field_trial_unittest.cc to the SCons build.

base/base_unittests.scons

 # Copyright (c) 2006-2008 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.
 
 __doc__ = """
 Configuration for building base_unittests{,.exe}.
 """
 
 Import('env')
 
@@ skipping 65 matching lines @@
   )
 
 # These test files work on *all* platforms; tests that don't work
 # cross-platform live below.
 input_files = [
     'at_exit_unittest.cc',
     'atomicops_unittest.cc',
     'clipboard_unittest.cc',
     'command_line_unittest.cc',
     'condition_variable_unittest.cc',
+    'field_trial_unittest.cc',
     'file_path_unittest.cc',
     'file_util_unittest.cc',
     'histogram_unittest.cc',
     'hmac_unittest.cc',
     'idletimer_unittest.cc',
     'json_reader_unittest.cc',
     'json_writer_unittest.cc',
     'lazy_instance_unittest.cc',
     'linked_ptr_unittest.cc',
     'message_loop_unittest.cc',
@@ skipping 94 matching lines @@
 
 env.Alias('base', installed_base_unittests)
 
 # TODO(sgk) should this be moved into base.lib like everything else?  This will
 # require updating a bunch of other SConscripts which link directly against
 # this generated object file.
 env.StaticObject('perftimer.cc')
 
 # Since run_all_perftests supplies a main, we cannot have it in base.lib
 env.StaticObject('run_all_perftests.cc')