Rename frame_create and frame_set_child_size with a window_ prefix

This is to avoid a collision with an actual frame structure.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
diff --git a/clients/resizor.c b/clients/resizor.c
index 68e4bf9..0f98d0b 100644
--- a/clients/resizor.c
+++ b/clients/resizor.c
@@ -235,7 +235,7 @@
 
 	resizor = xzalloc(sizeof *resizor);
 	resizor->window = window_create(display);
-	resizor->widget = frame_create(resizor->window, resizor);
+	resizor->widget = window_frame_create(resizor->window, resizor);
 	window_set_title(resizor->window, "Wayland Resizor");
 	resizor->display = display;