[Sync] Refactor sync datatype error handling.

chrome/chrome.gyp

 # Copyright (c) 2011 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,
 
     'variables': {
       'version_py_path': 'tools/build/version.py',
       'version_path': 'VERSION',
@@ skipping 563 matching lines @@
       'type': 'static_library',
       'sources': [
         'browser/sync/api/syncable_service.cc',
         'browser/sync/api/syncable_service.h',
         'browser/sync/api/sync_data.h',
         'browser/sync/api/sync_data.cc',
         'browser/sync/api/sync_change.h',
         'browser/sync/api/sync_change.cc',
         'browser/sync/api/sync_change_processor.h',
         'browser/sync/api/sync_change_processor.cc',
+        'browser/sync/api/sync_error.h',
+        'browser/sync/api/sync_error.cc',
       ],
       'include_dirs': [
         '..',
       ],
       'dependencies': [
         '../base/base.gyp:base',
         'browser/sync/protocol/sync_proto.gyp:sync_proto_cpp',
         'sync',
       ],
       'export_dependent_settings': [
@@ skipping 1104 matching lines @@
             'destination': '<(PRODUCT_DIR)',
             'files': [
               '<(INTERMEDIATE_DIR)/repack/chrome.pak'
             ],
           },
         ],
       }],  # targets
     }],  # os_posix == 1 and OS != "mac"
   ],  # 'conditions'
 }