mus: Use TooltipManagerAura in NativeWidgetMus.

ui/views/mus/window_manager_connection.h

Index: ui/views/mus/window_manager_connection.h
diff --git a/ui/views/mus/window_manager_connection.h b/ui/views/mus/window_manager_connection.h
index cad161ac06123b2a1e6a2e991ff3a57ac4dd45ce..25b6b5756551ee3d859f42bdf6620bb43ddc290e 100644
--- a/ui/views/mus/window_manager_connection.h
+++ b/ui/views/mus/window_manager_connection.h
@@ -9,6 +9,7 @@
 
 #include <map>
 #include <memory>
+#include <set>
 #include <string>
 #include <vector>
 
@@ -39,6 +40,10 @@ namespace internal {
 class NativeWidgetDelegate;
 }
 
+namespace test {
+class WindowManagerConnectionTestApi;
+}
+
 // Provides configuration to mus in views. This consists of the following:
 // . Provides a Screen implementation backed by mus.
 // . Provides a Clipboard implementation backed by mus.
@@ -82,6 +87,8 @@ class VIEWS_MUS_EXPORT WindowManagerConnection
   const std::set<ui::Window*>& GetRoots() const;
 
  private:
+  friend class test::WindowManagerConnectionTestApi;
+
   WindowManagerConnection(
       shell::Connector* connector,
       const shell::Identity& identity,
@@ -97,6 +104,7 @@ class VIEWS_MUS_EXPORT WindowManagerConnection
   // ScreenMusDelegate:
   void OnWindowManagerFrameValuesChanged() override;
   gfx::Point GetCursorScreenPoint() override;
+  ui::Window* GetWindowAtScreenPoint(const gfx::Point& point) override;
 
   // ui:OSExchangeDataProviderFactory::Factory:
   std::unique_ptr<OSExchangeData::Provider> BuildProvider() override;