[Sync] Refactor sync configuration logic.

sync/sync.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,
   },
   'targets': [
     # The core sync library.
@@ skipping 353 matching lines @@
         'internal_api/public/syncable/model_type_test_util.cc',
         'internal_api/public/syncable/model_type_test_util.h',
         'js/js_test_util.cc',
         'js/js_test_util.h',
         'notifier/mock_invalidation_state_tracker.cc',
         'notifier/mock_invalidation_state_tracker.h',
         'sessions/test_util.cc',
         'sessions/test_util.h',
         'syncable/syncable_mock.cc',
         'syncable/syncable_mock.h',
+        'test/callback_counter.h',
         'test/fake_encryptor.cc',
         'test/fake_encryptor.h',
         'test/fake_extensions_activity_monitor.cc',
         'test/fake_extensions_activity_monitor.h',
         'test/null_directory_change_delegate.cc',
         'test/null_directory_change_delegate.h',
         'test/null_transaction_observer.cc',
         'test/null_transaction_observer.h',
         'test/engine/test_directory_setter_upper.cc',
         'test/engine/test_directory_setter_upper.h',
@@ skipping 379 matching lines @@
             'test_suite_name': 'sync_unit_tests',
             'input_shlib_path': '<(SHARED_LIB_DIR)/<(SHARED_LIB_PREFIX)sync_unit_tests<(SHARED_LIB_SUFFIX)',
             'input_jars_paths': [ '<(PRODUCT_DIR)/lib.java/chromium_base.jar', ],
           },
           'includes': [ '../build/apk_test.gypi' ],
         },
       ],
     }],
   ],
 }