[Sync] Rework SharedValue<T> into Immutable<T>

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 687 matching lines @@
         'browser/sync/syncable/syncable_id.cc',
         'browser/sync/syncable/syncable_id.h',
         'browser/sync/syncable/syncable_enum_conversions.cc',
         'browser/sync/syncable/syncable_enum_conversions.h',
         'browser/sync/syncable/transaction_observer.h',
         'browser/sync/util/cryptographer.cc',
         'browser/sync/util/cryptographer.h',
         'browser/sync/util/dbgq.h',
         'browser/sync/util/extensions_activity_monitor.cc',
         'browser/sync/util/extensions_activity_monitor.h',
+        'browser/sync/util/immutable.h',
         'browser/sync/util/logging.cc',
         'browser/sync/util/logging.h',
         'browser/sync/util/nigori.cc',
         'browser/sync/util/nigori.h',
         'browser/sync/util/oauth.cc',
         'browser/sync/util/oauth.h',
-        'browser/sync/util/shared_value.h',
         'browser/sync/util/sqlite_utils.cc',
         'browser/sync/util/sqlite_utils.h',
         'browser/sync/util/user_settings.cc',
         'browser/sync/util/user_settings.h',
         'browser/sync/util/user_settings_posix.cc',
         'browser/sync/util/user_settings_win.cc',
         'browser/sync/weak_handle.cc',
         'browser/sync/weak_handle.h',
       ],
       'include_dirs': [
@@ skipping 994 matching lines @@
             'destination': '<(PRODUCT_DIR)',
             'files': [
               '<(INTERMEDIATE_DIR)/repack/chrome.pak'
             ],
           },
         ],
       }],  # targets
     }],  # OS != "mac"
   ],  # 'conditions'
 }