[Sync] Create new top-level sync/ directory

sync/protocol/sync_proto.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': [
     {
@@ skipping 15 matching lines @@
         'preference_specifics.proto',
         'search_engine_specifics.proto',
         'session_specifics.proto',
         'sync.proto',
         'sync_enums.proto',
         'test.proto',
         'theme_specifics.proto',
         'typed_url_specifics.proto',
       ],
       'variables': {
-        'proto_out_dir': 'chrome/browser/sync/protocol',
+        'proto_out_dir': 'sync/protocol',
       },
-      'includes': ['../../../../build/protoc.gypi'],
+      'includes': ['../../build/protoc.gypi'],
     },
   ],
 }