Pass args to SyncManager::Init via a struct.

sync/internal_api/sync_rollback_manager.h

Index: sync/internal_api/sync_rollback_manager.h
diff --git a/sync/internal_api/sync_rollback_manager.h b/sync/internal_api/sync_rollback_manager.h
index ee7144725e9ff96bfe1abc814e9c71be6ed5c5f9..ce40b7296397b2305fef3ab171b4b5eeb526e00f 100644
--- a/sync/internal_api/sync_rollback_manager.h
+++ b/sync/internal_api/sync_rollback_manager.h
@@ -22,23 +22,7 @@ class SYNC_EXPORT_PRIVATE SyncRollbackManager : public SyncRollbackManagerBase {
   virtual ~SyncRollbackManager();
 
   // SyncManager implementation.
-  virtual void Init(
-      const base::FilePath& database_location,
-      const WeakHandle<JsEventHandler>& event_handler,
-      const GURL& service_url,
-      scoped_ptr<HttpPostProviderFactory> post_factory,
-      const std::vector<scoped_refptr<ModelSafeWorker> >& workers,
-      ExtensionsActivity* extensions_activity,
-      SyncManager::ChangeDelegate* change_delegate,
-      const SyncCredentials& credentials,
-      const std::string& invalidator_client_id,
-      const std::string& restored_key_for_bootstrapping,
-      const std::string& restored_keystore_key_for_bootstrapping,
-      InternalComponentsFactory* internal_components_factory,
-      Encryptor* encryptor,
-      scoped_ptr<UnrecoverableErrorHandler> unrecoverable_error_handler,
-      ReportUnrecoverableErrorFunction report_unrecoverable_error_function,
-      CancelationSignal* cancelation_signal) OVERRIDE;
+  virtual void Init(InitArgs* args) OVERRIDE;
   virtual void StartSyncingNormally(
       const ModelSafeRoutingInfo& routing_info) OVERRIDE;