[Sync] Introduce GmsCoreSyncListener.

components/browser_sync/browser/profile_sync_service.cc

 // 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.
 
 #include "components/browser_sync/browser/profile_sync_service.h"
 
 #include <cstddef>
 #include <map>
 #include <vector>
 
@@ skipping 1845 matching lines @@
   }
   return registered_types;
 }
 
 bool ProfileSyncService::IsUsingSecondaryPassphrase() const {
   syncer::PassphraseType passphrase_type = GetPassphraseType();
   return passphrase_type == syncer::FROZEN_IMPLICIT_PASSPHRASE ||
          passphrase_type == syncer::CUSTOM_PASSPHRASE;
 }
 
+std::string ProfileSyncService::GetCustomPassphraseKey() const {
+  sync_driver::SystemEncryptor encryptor;
+  syncer::Cryptographer cryptographer(&encryptor);
+  cryptographer.Bootstrap(sync_prefs_.GetEncryptionBootstrapToken());
+  return cryptographer.GetDefaultNigoriKeyData();
+}
+
 syncer::PassphraseType ProfileSyncService::GetPassphraseType() const {
   return backend_->GetPassphraseType();
 }
 
 base::Time ProfileSyncService::GetExplicitPassphraseTime() const {
   return backend_->GetExplicitPassphraseTime();
 }
 
 bool ProfileSyncService::IsCryptographerReady(
     const syncer::BaseTransaction* trans) const {
@@ skipping 820 matching lines @@
 }
 
 std::string ProfileSyncService::unrecoverable_error_message() const {
   return unrecoverable_error_message_;
 }
 
 tracked_objects::Location ProfileSyncService::unrecoverable_error_location()
     const {
   return unrecoverable_error_location_;
 }