Makes it possible for clients to directly create WindowTreeHostMus

ui/aura/window_port_local.cc

Index: ui/aura/window_port_local.cc
diff --git a/ui/aura/window_port_local.cc b/ui/aura/window_port_local.cc
index f11830145879f1ed9e612becb651226d386a36ba..9037c2602116afcb72a7d62db2d00c3a1ba311d7 100644
--- a/ui/aura/window_port_local.cc
+++ b/ui/aura/window_port_local.cc
@@ -59,12 +59,7 @@ WindowPortLocal::WindowPortLocal(Window* window) : window_(window) {}
 
 WindowPortLocal::~WindowPortLocal() {}
 
-std::unique_ptr<WindowPortInitData> WindowPortLocal::OnPreInit(Window* window) {
-  return nullptr;
-}
-
-void WindowPortLocal::OnPostInit(
-    std::unique_ptr<WindowPortInitData> init_data) {}
+void WindowPortLocal::OnPreInit(Window* window) {}
 
 void WindowPortLocal::OnDeviceScaleFactorChanged(float device_scale_factor) {
   ScopedCursorHider hider(window_);