Drop unnecessary override of OnWindowBoundsChanged in NativeWidgetMus::MusWindowObserver

ui/views/mus/window_tree_host_mus.cc

Index: ui/views/mus/window_tree_host_mus.cc
diff --git a/ui/views/mus/window_tree_host_mus.cc b/ui/views/mus/window_tree_host_mus.cc
index a497e2cd25915b9a5e871181598cb309e1d1eb59..4aed38c33ded4d4c58ce732fa4154da1717ce9d1 100644
--- a/ui/views/mus/window_tree_host_mus.cc
+++ b/ui/views/mus/window_tree_host_mus.cc
@@ -38,7 +38,10 @@ WindowTreeHostMus::WindowTreeHostMus(NativeWidgetMus* native_widget,
   // TODO(markdittmer): Use correct device-scale-factor from |window|.
   OnAcceleratedWidgetAvailable(accelerated_widget, 1.f);
 
-  SetPlatformWindow(base::WrapUnique(new ui::StubWindow(nullptr)));
+  SetPlatformWindow(base::WrapUnique(new ui::StubWindow(
+      this,
+      false)));  // Do not advertise accelerated widget; already set manually.
+
   // Initialize the stub platform window bounds to those of the mus::Window.
   platform_window()->SetBounds(window->bounds());