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/window.h b/clients/window.h
index 4427ab5..6c2275b 100644
--- a/clients/window.h
+++ b/clients/window.h
@@ -508,10 +508,11 @@
 widget_schedule_redraw(struct widget *widget);
 
 struct widget *
-frame_create(struct window *window, void *data);
+window_frame_create(struct window *window, void *data);
 
 void
-frame_set_child_size(struct widget *widget, int child_width, int child_height);
+window_frame_set_child_size(struct widget *widget, int child_width,
+			    int child_height);
 
 void
 input_set_pointer_image(struct input *input, int pointer);