Changes top level window creation to include window state in callback

components/mus/public/interfaces/window_tree.mojom

Index: components/mus/public/interfaces/window_tree.mojom
diff --git a/components/mus/public/interfaces/window_tree.mojom b/components/mus/public/interfaces/window_tree.mojom
index 851731502686dd30422702aa50d05c5d8d0b82e4..a1e8152c6986e628d6156a051f13157c0647e596 100644
--- a/components/mus/public/interfaces/window_tree.mojom
+++ b/components/mus/public/interfaces/window_tree.mojom
@@ -93,7 +93,9 @@ interface WindowTree {
             uint32 window_id,
             map<string, array<uint8>>? properties);
 
-  // Requests the WindowManager to create a new top level window.
+  // Requests the WindowManager to create a new top level window. On success
+  // OnTopLevelCreated() is called with the WindowData for the new window. On
+  // failure OnChangeCompleted() is called.
   // TODO(sky): this likely needs context, maybe in |properties|.
   NewTopLevelWindow(uint32 change_id,
                     uint32 window_id,
@@ -265,6 +267,9 @@ interface WindowTreeClient {
   // previously embedded in. See Embed() for more information.
   OnUnembed(uint32 window);
 
+  // Called in response to NewTopLevelWindow() successfully completing.
+  OnTopLevelCreated(uint32 change_id, WindowData data);
+
   // Invoked when a window's bounds have changed.
   OnWindowBoundsChanged(uint32 window,
                         mojo.Rect old_bounds,