convert //mash to std::unique_ptr

mash/example/window_type_launcher/window_type_launcher.cc

Index: mash/example/window_type_launcher/window_type_launcher.cc
diff --git a/mash/example/window_type_launcher/window_type_launcher.cc b/mash/example/window_type_launcher/window_type_launcher.cc
index 0547e84b3e02a6fb7c1838a6375fc77269ee303c..6b65961caead6ed1ddb9b851bde1505a069d4a88 100644
--- a/mash/example/window_type_launcher/window_type_launcher.cc
+++ b/mash/example/window_type_launcher/window_type_launcher.cc
@@ -360,7 +360,7 @@ class WindowTypeLauncherView : public views::WidgetDelegateView,
   views::LabelButton* examples_button_;
   views::LabelButton* show_hide_window_button_;
   views::LabelButton* show_web_notification_;
-  scoped_ptr<views::MenuRunner> menu_runner_;
+  std::unique_ptr<views::MenuRunner> menu_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTypeLauncherView);
 };