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

chrome/browser/sync/glue/sync_backend_host.h

 // 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.
 
 #ifndef CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_H_
 #define CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread.h"
 #include "components/sync_driver/backend_data_type_configurer.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/configure_reason.h"
 #include "sync/internal_api/public/sessions/sync_session_snapshot.h"
+#include "sync/internal_api/public/shutdown_reason.h"
 #include "sync/internal_api/public/sync_context_proxy.h"
 #include "sync/internal_api/public/sync_manager.h"
 #include "sync/internal_api/public/sync_manager_factory.h"
 #include "sync/internal_api/public/util/report_unrecoverable_error_function.h"
 #include "sync/internal_api/public/util/unrecoverable_error_handler.h"
 #include "sync/internal_api/public/util/weak_handle.h"
 
 class GURL;
 
 namespace base {
@@ skipping 79 matching lines @@
   virtual bool SetDecryptionPassphrase(const std::string& passphrase)
       WARN_UNUSED_RESULT = 0;
 
   // Called on |frontend_loop_| to kick off shutdown procedure.  Attempts to cut
   // short any long-lived or blocking sync thread tasks so that the shutdown on
   // sync thread task that we're about to post won't have to wait very long.
   virtual void StopSyncingForShutdown() = 0;
 
   // Called on |frontend_loop_| to kick off shutdown.
   // See the implementation and Core::DoShutdown for details.
-  // Must be called *after* StopSyncingForShutdown. Caller should claim sync
-  // thread using STOP_AND_CLAIM_THREAD or DISABLE_AND_CLAIM_THREAD if sync
-  // backend might be recreated later because otherwise:
-  // * sync loop may be stopped on main loop and cause it to be blocked.
-  // * new/old backend may interfere with each other if new backend is created
-  //   before old one finishes cleanup.
-  enum ShutdownOption {
-    STOP,                      // Stop syncing and let backend stop sync thread.
-    STOP_AND_CLAIM_THREAD,     // Stop syncing and return sync thread.
-    DISABLE_AND_CLAIM_THREAD,  // Disable sync and return sync thread.
-  };
-  virtual scoped_ptr<base::Thread> Shutdown(ShutdownOption option) = 0;
+  // Must be called *after* StopSyncingForShutdown.
+  // For any reason other than BROWSER_SHUTDOWN, caller should claim sync
+  // thread because:
+  // * during browser shutdown sync thread is not claimed to avoid blocking
+  //   browser shutdown on sync shutdown.
+  // * otherwise sync thread is claimed so that if sync backend is recreated
+  //   later, initialization of new backend is serialized on previous sync
+  //   thread after cleanup of previous backend to avoid old/new backends
+  //   interfere with each other.
+  virtual scoped_ptr<base::Thread> Shutdown(syncer::ShutdownReason reason) = 0;
 
   // Removes all current registrations from the backend on the
   // InvalidationService.
   virtual void UnregisterInvalidationIds() = 0;
 
   // Changes the set of data types that are currently being synced.
   // The ready_task will be run when configuration is done with the
   // set of all types that failed configuration (i.e., if its argument
   // is non-empty, then an error was encountered).
   virtual void ConfigureDataTypes(
@@ skipping 76 matching lines @@
   virtual void DisableDirectoryTypeDebugInfoForwarding() = 0;
 
   virtual base::MessageLoop* GetSyncLoopForTesting() = 0;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHost);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_SYNC_BACKEND_HOST_H_