[Sync] Replace typedef with using.

components/sync/engine/sync_engine.h

Index: components/sync/engine/sync_engine.h
diff --git a/components/sync/engine/sync_engine.h b/components/sync/engine/sync_engine.h
index 03eadfa0e20397acc5e826d7b9901af66077d572..581c74a00333948f540d96b5d79771da6cf6270f 100644
--- a/components/sync/engine/sync_engine.h
+++ b/components/sync/engine/sync_engine.h
@@ -42,10 +42,10 @@ class UnrecoverableErrorHandler;
 // interface will handle crossing threads if necessary.
 class SyncEngine : public ModelTypeConfigurer {
  public:
-  typedef SyncStatus Status;
-  typedef base::Callback<std::unique_ptr<HttpPostProviderFactory>(
-      CancelationSignal*)>
-      HttpPostProviderFactoryGetter;
+  using Status = SyncStatus;
+  using HttpPostProviderFactoryGetter =
+      base::Callback<std::unique_ptr<HttpPostProviderFactory>(
+          CancelationSignal*)>;
 
   // Utility struct for holding initialization options.
   struct InitParams {