sync: Add --enable-sync-sessions-v2 and necessary plumbing to use SessionsSyncManager.

chrome/browser/extensions/api/signed_in_devices/signed_in_devices_api.cc

 // Copyright (c) 2013 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.
 
 #include "chrome/browser/extensions/api/signed_in_devices/signed_in_devices_api.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/api/signed_in_devices/id_mapping_helper.h"
@@ skipping 74 matching lines @@
                                pss,
                                extension_prefs);
 }
 
 scoped_ptr<DeviceInfo> GetLocalDeviceInfo(const std::string& extension_id,
                                           Profile* profile) {
   ProfileSyncService* pss = ProfileSyncServiceFactory::GetForProfile(profile);
   if (!pss) {
     return scoped_ptr<DeviceInfo>();
   }
-  std::string guid = pss->GetLocalDeviceGUID();
+  std::string guid = pss->GetLocalSyncCacheGUID();
   scoped_ptr<DeviceInfo> device = GetDeviceInfoForClientId(guid,
                                                            extension_id,
                                                            profile);
   return device.Pass();
 }
 
 bool SignedInDevicesGetFunction::RunImpl() {
   scoped_ptr<api::signed_in_devices::Get::Params> params(
       api::signed_in_devices::Get::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
@@ skipping 21 matching lines @@
        ++it) {
     result->Append((*it)->ToValue());
   }
 
   SetResult(result.release());
   return true;
 }
 
 }  // namespace extensions