Promotes WmWindowMus functions to WmWindowAura and nukes WmWindowMus

ash/mus/bridge/wm_lookup_mus.cc

Index: ash/mus/bridge/wm_lookup_mus.cc
diff --git a/ash/mus/bridge/wm_lookup_mus.cc b/ash/mus/bridge/wm_lookup_mus.cc
index b9b0be19a1704e38dd3a82b90279fd2e43185773..685d1faebd0d3ed7a11516c6f9d1780af52e1073 100644
--- a/ash/mus/bridge/wm_lookup_mus.cc
+++ b/ash/mus/bridge/wm_lookup_mus.cc
@@ -4,8 +4,8 @@
 
 #include "ash/mus/bridge/wm_lookup_mus.h"
 
+#include "ash/aura/wm_window_aura.h"
 #include "ash/mus/bridge/wm_shell_mus.h"
-#include "ash/mus/bridge/wm_window_mus.h"
 #include "ash/mus/root_window_controller.h"
 #include "ui/views/widget/widget.h"
 
@@ -29,7 +29,7 @@ ash::RootWindowController* WmLookupMus::GetRootWindowControllerWithDisplayId(
 }
 
 WmWindow* WmLookupMus::GetWindowForWidget(views::Widget* widget) {
-  return WmWindowMus::Get(widget);
+  return ash::WmWindowAura::Get(widget->GetNativeWindow());
 }
 
 }  // namespace mus