Update {virtual,override} to follow C++11 style in components.

components/leveldb_proto/proto_database_impl.h

Index: components/leveldb_proto/proto_database_impl.h
diff --git a/components/leveldb_proto/proto_database_impl.h b/components/leveldb_proto/proto_database_impl.h
index cc5622122c3b29e76d88e5d53bd13b97985135ae..adf79bd7ad5e654ca5e18bb975860297c71f1d64 100644
--- a/components/leveldb_proto/proto_database_impl.h
+++ b/components/leveldb_proto/proto_database_impl.h
@@ -35,19 +35,18 @@ class ProtoDatabaseImpl : public ProtoDatabase<T> {
   explicit ProtoDatabaseImpl(
       scoped_refptr<base::SequencedTaskRunner> task_runner);
 
-  virtual ~ProtoDatabaseImpl();
+  ~ProtoDatabaseImpl() override;
 
   // ProtoDatabase implementation.
   // TODO(cjhopman): Perhaps Init() shouldn't be exposed to users and not just
   //     part of the constructor
-  virtual void Init(const base::FilePath& database_dir,
-                    typename ProtoDatabase<T>::InitCallback callback) override;
-  virtual void UpdateEntries(
+  void Init(const base::FilePath& database_dir,
+            typename ProtoDatabase<T>::InitCallback callback) override;
+  void UpdateEntries(
       scoped_ptr<typename ProtoDatabase<T>::KeyEntryVector> entries_to_save,
       scoped_ptr<KeyVector> keys_to_remove,
       typename ProtoDatabase<T>::UpdateCallback callback) override;
-  virtual void LoadEntries(
-      typename ProtoDatabase<T>::LoadCallback callback) override;
+  void LoadEntries(typename ProtoDatabase<T>::LoadCallback callback) override;
 
   // Allow callers to provide their own Database implementation.
   void InitWithDatabase(scoped_ptr<LevelDB> database,