[Sync] Make BackendMigrator not wait for full sync cycles

chrome/browser/sync/internal_api/sync_manager.h

Index: chrome/browser/sync/internal_api/sync_manager.h
diff --git a/chrome/browser/sync/internal_api/sync_manager.h b/chrome/browser/sync/internal_api/sync_manager.h
index 2dfe1259170ce337e09796d94877abb854762b30..0fbb6dcebe5d4d0ec46539481e9a9aa204ab4512 100644
--- a/chrome/browser/sync/internal_api/sync_manager.h
+++ b/chrome/browser/sync/internal_api/sync_manager.h
@@ -457,16 +457,16 @@ class SyncManager {
 
   // Puts the SyncScheduler into a mode where no normal nudge or poll traffic
   // will occur, but calls to RequestConfig will be supported.  If |callback|
-  // is provided, it will be invoked (from the internal SyncScheduler) when
+  // is non-null, it will be invoked (from the internal SyncScheduler) when
   // the thread has changed to configuration mode.
-  void StartConfigurationMode(ModeChangeCallback* callback);
+  void StartConfigurationMode(const base::Closure& callback);
 
   // Switches the mode of operation to CONFIGURATION_MODE and
   // schedules a config task to fetch updates for |types|.
   void RequestConfig(const syncable::ModelTypeBitSet& types,
      sync_api::ConfigureReason reason);
 
-  void RequestCleanupDisabledTypes();
+  void RequestCleanupDisabledTypes(const base::Closure& callback);
 
   // Request a clearing of all data on the server
   void RequestClearServerData();