mus: Use TooltipManagerAura in NativeWidgetMus.

ui/views/mus/native_widget_mus.h

Index: ui/views/mus/native_widget_mus.h
diff --git a/ui/views/mus/native_widget_mus.h b/ui/views/mus/native_widget_mus.h
index acee4f0a6c26f8ebc7e00e25d3b678091f4f3b4c..71bdcbf07d7dc4048f600921ed145b9a3b4e39bd 100644
--- a/ui/views/mus/native_widget_mus.h
+++ b/ui/views/mus/native_widget_mus.h
@@ -54,8 +54,12 @@ class FocusController;
 }
 
 namespace views {
+namespace corewm {
+class TooltipController;
+}
 class DropHelper;
 class DropTargetMus;
+class TooltipManagerAura;
 class WidgetDelegate;
 
 // An implementation of NativeWidget that binds to a ui::Window. Because Aura
@@ -300,6 +304,9 @@ class VIEWS_MUS_EXPORT NativeWidgetMus
   std::unique_ptr<DropHelper> drop_helper_;
   int last_drop_operation_;
 
+  std::unique_ptr<corewm::TooltipController> tooltip_controller_;
+  std::unique_ptr<TooltipManagerAura> tooltip_manager_;
+
   base::WeakPtrFactory<NativeWidgetMus> close_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeWidgetMus);