Fix X11DesktopHandler::ActivateWindow on Unity for known user gestures

ui/views/widget/desktop_aura/desktop_window_tree_host_win.h

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
index 29aeb0242632b5103d6b4f85fadc2cd7145615e6..6cea62ebd7faf3d5c3a39b717ecd3228ae0d452e 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_win.h
@@ -68,6 +68,7 @@ class VIEWS_EXPORT DesktopWindowTreeHostWin
   gfx::Rect GetWorkAreaBoundsInScreen() const override;
   void SetShape(gfx::NativeRegion native_region) override;
   void Activate() override;
+  void ActivateForUserGesture() override;
   void Deactivate() override;
   bool IsActive() const override;
   void Maximize() override;