void gtk_test_widget_wait_for_draw ( GtkWidget* widget )
Enters the main loop and waits for
widget to be “drawn”.
In this context that means it waits for the frame clock of
widget to have run a full styling, layout and drawing cycle.
This function is intended to be used for syncing with actions that
widget relayouting or on interaction with the display server.
The widget to wait for.
The data is owned by the caller of the function.