Wire sync shutdown reason from PSS all the way down to sync manager.

chrome/browser/sync/glue/sync_backend_host_impl.h

 // Copyright 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.
 
 #ifndef CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_IMPL_H_
 #define CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_IMPL_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 83 matching lines @@
       syncer::NetworkResources* network_resources) OVERRIDE;
   virtual void UpdateCredentials(
       const syncer::SyncCredentials& credentials) OVERRIDE;
   virtual void StartSyncingWithServer() OVERRIDE;
   virtual void SetEncryptionPassphrase(
       const std::string& passphrase,
       bool is_explicit) OVERRIDE;
   virtual bool SetDecryptionPassphrase(const std::string& passphrase)
       OVERRIDE WARN_UNUSED_RESULT;
   virtual void StopSyncingForShutdown() OVERRIDE;
-  virtual scoped_ptr<base::Thread> Shutdown(ShutdownOption option) OVERRIDE;
+  virtual scoped_ptr<base::Thread> Shutdown(syncer::ShutdownReason reason)
+      OVERRIDE;
   virtual void UnregisterInvalidationIds() OVERRIDE;
   virtual void ConfigureDataTypes(
       syncer::ConfigureReason reason,
       const DataTypeConfigStateMap& config_state_map,
       const base::Callback<void(syncer::ModelTypeSet,
                                 syncer::ModelTypeSet)>& ready_task,
       const base::Callback<void()>& retry_callback) OVERRIDE;
   virtual void ActivateDataType(
      syncer::ModelType type, syncer::ModelSafeGroup group,
      sync_driver::ChangeProcessor* change_processor) OVERRIDE;
@@ skipping 251 matching lines @@
 
   base::WeakPtrFactory<SyncBackendHostImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHostImpl);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_IMPL_H_