Split testing_pref_service.h/.cc into two parts, generic vs. Chrome-specific.

chrome/chrome_tests_unit.gypi

  # Copyright 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.
 {
   'targets': [
     {
       # This target contains mocks and test utilities that don't belong in
       # production libraries but are used by more than one test executable.
       'target_name': 'test_support_common',
       'type': 'static_library',
@@ skipping 212 matching lines @@
         'test/base/test_launcher_utils.cc',
         'test/base/test_launcher_utils.h',
         'test/base/test_location_bar.cc',
         'test/base/test_location_bar.h',
         'test/base/test_tab_strip_model_observer.cc',
         'test/base/test_tab_strip_model_observer.h',
         'test/base/testing_browser_process.cc',
         'test/base/testing_browser_process.h',
         'test/base/testing_pref_service.cc',
         'test/base/testing_pref_service.h',
+        'test/base/testing_pref_service_syncable.cc',
+        'test/base/testing_pref_service_syncable.h',
         'test/base/testing_profile.cc',
         'test/base/testing_profile.h',
         'test/base/testing_profile_manager.cc',
         'test/base/testing_profile_manager.h',
         'test/base/thread_observer_helper.h',
         'test/base/tracing.cc',
         'test/base/tracing.h',
         'test/base/ui_test_utils.cc',
         'test/base/ui_test_utils.h',
         'test/base/uma_histogram_helper.cc',
@@ skipping 2129 matching lines @@
               # more details.
               'DebugInformationFormat': '3',
               'ProgramDataBaseFileName': '<(PRODUCT_DIR)/unit_tests.exe.pdb',
             },
           },
         },
       ],
     }],
   ],  # 'conditions'
 }