mus: Adds WindowManagerDelegate::OnWmConnected()

ui/aura/test/mus/window_tree_client_private.h

Index: ui/aura/test/mus/window_tree_client_private.h
diff --git a/ui/aura/test/mus/window_tree_client_private.h b/ui/aura/test/mus/window_tree_client_private.h
index e600127b488449b17c44437e2c421ba0d59c0f31..3c2279df44f4acca272bfef84588d640ec7cd7a6 100644
--- a/ui/aura/test/mus/window_tree_client_private.h
+++ b/ui/aura/test/mus/window_tree_client_private.h
@@ -55,6 +55,8 @@ class WindowTreeClientPrivate {
 
   void CallOnCaptureChanged(Window* new_capture, Window* old_capture);
 
+  void CallOnConnect();
+
   // Sets the WindowTree and client id.
   void SetTreeAndClientId(ui::mojom::WindowTree* window_tree,
                           ClientSpecificId client_id);