Revert of 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 71bdcbf07d7dc4048f600921ed145b9a3b4e39bd..acee4f0a6c26f8ebc7e00e25d3b678091f4f3b4c 100644
--- a/ui/views/mus/native_widget_mus.h
+++ b/ui/views/mus/native_widget_mus.h
@@ -54,12 +54,8 @@
 }
 
 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
@@ -304,9 +300,6 @@
   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);