Standardize usage of virtual/override/final in sync/

sync/util/test_unrecoverable_error_handler.h

Index: sync/util/test_unrecoverable_error_handler.h
diff --git a/sync/util/test_unrecoverable_error_handler.h b/sync/util/test_unrecoverable_error_handler.h
index c880ffd38dcc801c62d2b4ee4e79ce5356fec6b8..ae0610c576b2af7ed029f088a3775358b902782a 100644
--- a/sync/util/test_unrecoverable_error_handler.h
+++ b/sync/util/test_unrecoverable_error_handler.h
@@ -15,10 +15,10 @@ namespace syncer {
 class TestUnrecoverableErrorHandler : public UnrecoverableErrorHandler {
  public:
   TestUnrecoverableErrorHandler();
-  virtual ~TestUnrecoverableErrorHandler();
+  ~TestUnrecoverableErrorHandler() override;
 
-  virtual void OnUnrecoverableError(const tracked_objects::Location& from_here,
-                                    const std::string& message) override;
+  void OnUnrecoverableError(const tracked_objects::Location& from_here,
+                            const std::string& message) override;
 };
 
 }  // namespace syncer