servo: Merge #10626 - Use the document base url when resolving iframe URLs (from sliz1:10576); r=KiChjang

Fixes #10576.

Source-Repo: https://github.com/servo/servo
Source-Revision: 7faa3ed9cb87ebfa62554940e916bb7e4d04512b

servo/components/script/dom/htmliframeelement.rs

@@ -82,8 +82,7 @@ impl HTMLIFrameElement {
             if url.is_empty() {
                 None
             } else {
-                let window = window_from_node(self);
-                window.get_url().join(&url).ok()
+                document_from_node(self).base_url().join(&url).ok()
             }
         })
     }