Revert of Converts chrome to aura-mus

ui/views/mus/desktop_window_tree_host_mus.cc

Index: ui/views/mus/desktop_window_tree_host_mus.cc
diff --git a/ui/views/mus/desktop_window_tree_host_mus.cc b/ui/views/mus/desktop_window_tree_host_mus.cc
index c3097bd499666b4fe677a99dc499a001b7568652..12c9e7fd24c77fe6970f50b2b14516c6849938a4 100644
--- a/ui/views/mus/desktop_window_tree_host_mus.cc
+++ b/ui/views/mus/desktop_window_tree_host_mus.cc
@@ -180,11 +180,6 @@
       close_widget_factory_(this) {
   aura::Env::GetInstance()->AddObserver(this);
   MusClient::Get()->AddObserver(this);
-  // DesktopNativeWidgetAura registers the association between |content_window_|
-  // and Widget, but code may also want to go from the root (window()) to the
-  // Widget. This call enables that.
-  NativeWidgetAura::RegisterNativeWidgetForWindow(desktop_native_widget_aura,
-                                                  window());
   // TODO: use display id and bounds if available, likely need to pass in
   // InitParams for that.
 }