C++11 override style change for athena

athena/system/system_ui_impl.cc

Index: athena/system/system_ui_impl.cc
diff --git a/athena/system/system_ui_impl.cc b/athena/system/system_ui_impl.cc
index 64653bad988b1f1ab025b464a95d490bc66319c0..4033ddb48bcf38d231a749b730e2ecade88d8fae 100644
--- a/athena/system/system_ui_impl.cc
+++ b/athena/system/system_ui_impl.cc
@@ -34,7 +34,7 @@ class SystemInfoView : public views::View {
     AddChildView(status_icon_view_);
   }
 
-  virtual ~SystemInfoView() {
+  ~SystemInfoView() override {
   }
 
   // views::View:
@@ -78,7 +78,7 @@ class SystemUIImpl : public SystemUI {
     orientation_controller_->InitWith(blocking_task_runner);
   }
 
-  virtual ~SystemUIImpl() {
+  ~SystemUIImpl() override {
     // Stops file watching now if exists. Waiting until message loop shutdon
     // leads to FilePathWatcher crash.
     orientation_controller_->Shutdown();