Converts ash to use aura-mus

ash/aura/wm_root_window_controller_aura.cc

Index: ash/aura/wm_root_window_controller_aura.cc
diff --git a/ash/aura/wm_root_window_controller_aura.cc b/ash/aura/wm_root_window_controller_aura.cc
index eae1b44e73b537f6b35adf561b158dde6cc91211..6fdb4725b9e3b069a9b80231cf5b81b131e70465 100644
--- a/ash/aura/wm_root_window_controller_aura.cc
+++ b/ash/aura/wm_root_window_controller_aura.cc
@@ -11,6 +11,7 @@
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
+#include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_property.h"
@@ -55,6 +56,7 @@ const WmRootWindowControllerAura* WmRootWindowControllerAura::Get(
   if (wm_root_window_controller)
     return wm_root_window_controller;
 
+  DCHECK_EQ(aura::Env::Mode::LOCAL, aura::Env::GetInstance()->mode());
   // WmRootWindowControllerAura is owned by the RootWindowController's window.
   return new WmRootWindowControllerAura(root_window_controller);
 }