[Sync] Add support for performing a GetKey on startup.

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 59 matching lines @@
         'engine/build_commit_command.cc',
         'engine/build_commit_command.h',
         'engine/commit.cc',
         'engine/commit.h',
         'engine/conflict_resolver.cc',
         'engine/conflict_resolver.h',
         'engine/download_updates_command.cc',
         'engine/download_updates_command.h',
         'engine/get_commit_ids_command.cc',
         'engine/get_commit_ids_command.h',
+        'engine/get_key_command.cc',
+        'engine/get_key_command.h',
         'engine/model_changing_syncer_command.cc',
         'engine/model_changing_syncer_command.h',
         'engine/net/server_connection_manager.cc',
         'engine/net/server_connection_manager.h',
         'engine/net/url_translator.cc',
         'engine/net/url_translator.h',
         'engine/nudge_source.cc',
         'engine/nudge_source.h',
         'engine/process_commit_response_command.cc',
         'engine/process_commit_response_command.h',
@@ skipping 722 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' ],
         },
       ],
     }],
   ],
 }