Propagates window type properties during aura-mus window creation

ui/aura/mus/window_manager_delegate.h

Index: ui/aura/mus/window_manager_delegate.h
diff --git a/ui/aura/mus/window_manager_delegate.h b/ui/aura/mus/window_manager_delegate.h
index 478ce90f57494bb80a444a8afe5372f05a115dc1..ab99d44a2d462a7587c0abcb4a8d48903be5230d 100644
--- a/ui/aura/mus/window_manager_delegate.h
+++ b/ui/aura/mus/window_manager_delegate.h
@@ -94,8 +94,12 @@ class AURA_EXPORT WindowManagerDelegate {
   // supplied properties from the client requesting the new window. The
   // delegate may modify |properties| before calling NewWindow(), but the
   // delegate does *not* own |properties|, they are valid only for the life
-  // of OnWmCreateTopLevelWindow().
+  // of OnWmCreateTopLevelWindow(). |window_type| is the type of window
+  // requested by the client and is |null| if the client did not specify a
+  // type. use SetWindowType() with |window_type| (in property_utils.h) to
+  // configure the type on the newly created window.
   virtual Window* OnWmCreateTopLevelWindow(
+      const ui::mojom::WindowType* window_type,
       std::map<std::string, std::vector<uint8_t>>* properties) = 0;
 
   // Called when a Mus client's jankiness changes. |windows| is the set of