Standardize usage of virtual/override/final in sync/

sync/test/engine/mock_model_type_sync_proxy.h

Index: sync/test/engine/mock_model_type_sync_proxy.h
diff --git a/sync/test/engine/mock_model_type_sync_proxy.h b/sync/test/engine/mock_model_type_sync_proxy.h
index fd09927dc7b68c937c59df693ff24e7c8d2e8a8b..338a5ae57c17af20a2aed0f1e97513fb38b1a6f4 100644
--- a/sync/test/engine/mock_model_type_sync_proxy.h
+++ b/sync/test/engine/mock_model_type_sync_proxy.h
@@ -28,16 +28,14 @@ namespace syncer {
 class MockModelTypeSyncProxy : public ModelTypeSyncProxy {
  public:
   MockModelTypeSyncProxy();
-  virtual ~MockModelTypeSyncProxy();
+  ~MockModelTypeSyncProxy() override;
 
   // Implementation of ModelTypeSyncProxy.
-  virtual void OnCommitCompleted(
-      const DataTypeState& type_state,
-      const CommitResponseDataList& response_list) override;
-  virtual void OnUpdateReceived(
-      const DataTypeState& type_state,
-      const UpdateResponseDataList& response_list,
-      const UpdateResponseDataList& pending_updates) override;
+  void OnCommitCompleted(const DataTypeState& type_state,
+                         const CommitResponseDataList& response_list) override;
+  void OnUpdateReceived(const DataTypeState& type_state,
+                        const UpdateResponseDataList& response_list,
+                        const UpdateResponseDataList& pending_updates) override;
 
   // By default, this object behaves as if all messages are processed
   // immediately.  Sometimes it is useful to defer work until later, as might