[Sync] Make BackendMigrator not wait for full sync cycles

chrome/test/live_sync/live_sync_test.h

 // 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.
 
 #ifndef CHROME_TEST_LIVE_SYNC_LIVE_SYNC_TEST_H_
 #define CHROME_TEST_LIVE_SYNC_LIVE_SYNC_TEST_H_
 #pragma once
 
 #include "chrome/test/base/in_process_browser_test.h"
 
@@ skipping 124 matching lines @@
 
   // Checks if the datatype |type| is encrypted for profile |index|.
   bool IsEncrypted(int index, syncable::ModelType type);
 
   // Blocks until all sync clients have completed their mutual sync cycles.
   // Returns true if a quiescent state was successfully reached.
   bool AwaitQuiescence();
 
   // Returns true if the server being used supports controlling
   // notifications.
-  bool ServerSupportsNotificationControl();
+  bool ServerSupportsNotificationControl() const;
 
   // Disable notifications on the server.  This operation is available
   // only if ServerSupportsNotificationControl() returned true.
   void DisableNotifications();
 
+  // Enable notifications on the server.  This operation is available
+  // only if ServerSupportsNotificationControl() returned true.
+  void EnableNotifications();
+
   // Trigger a notification to be sent to all clients.  This operation
   // is available only if ServerSupportsNotificationControl() returned
   // true.
   void TriggerNotification(const syncable::ModelTypeSet& changed_types);
 
   // Returns true if the server being used supports injecting errors.
-  bool ServerSupportsErrorTriggering();
+  bool ServerSupportsErrorTriggering() const;
 
   // Triggers a migration for one or more datatypes, and waits
   // for the server to complete it.  This operation is available
   // only if ServerSupportsErrorTriggering() returned true.
   void TriggerMigrationDoneError(const syncable::ModelTypeSet& model_types);
 
   // Triggers the server to set its birthday to a random value thereby
   // the server would return a birthday error on next sync.
   void TriggerBirthdayError();
 
@@ skipping 136 matching lines @@
 
   // The URLFetcherFactory instance used to instantiate |fake_factory_|.
   scoped_ptr<URLFetcherFactory> factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LiveSyncTest);
 };
 
 DISABLE_RUNNABLE_METHOD_REFCOUNT(LiveSyncTest);
 
 #endif  // CHROME_TEST_LIVE_SYNC_LIVE_SYNC_TEST_H_