Auto merge of #13358 - rjgoldsborough:form-action-url-11219, r=mbrubeck

Form action url 11219

First pass at fixing #10580.
I've added a new macro that returns a DomString with either the attr val or the doc url.
I then made the form element use that macro on the action attribute.
I also added a test that contains an iframe with a form and base url that submits to a page in
a resources directory.

I made all these changes based on https://github.com/servo/servo/pull/11219#issuecomment-223318881.

The only thing I'm confused on is how to change step 8. It looks to just be getting the action so I'm wondering if I need to change either step 9 or 10 instead?

---

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #10580 (github issue number if applicable).

- [X] There are tests for these changes OR

using that macro with the form action,
making the form submit process use base url,
adding tests.

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components/script/dom/htmlformelement.rs

@@ -98,7 +98,7 @@ impl HTMLFormElementMethods for HTMLFormElement {
     make_setter!(SetAcceptCharset, "accept-charset");
 
     // https://html.spec.whatwg.org/multipage/#dom-fs-action
-    make_url_or_base_getter!(Action, "action");
+    make_string_or_document_url_getter!(Action, "action");
 
     // https://html.spec.whatwg.org/multipage/#dom-fs-action
     make_setter!(SetAction, "action");
@@ -295,7 +295,7 @@ impl HTMLFormElement {
     pub fn submit(&self, submit_method_flag: SubmittedFrom, submitter: FormSubmitter) {
         // Step 1
         let doc = document_from_node(self);
-        let base = doc.url();
+        let base = doc.base_url();
         // TODO: Handle browsing contexts (Step 2, 3)
         // Step 4
         if submit_method_flag == SubmittedFrom::NotFromForm &&

components/script/dom/macros.rs

@@ -123,6 +123,26 @@ macro_rules! make_url_or_base_getter(
     );
 );
 
+#[macro_export]
+macro_rules! make_string_or_document_url_getter(
+    ( $attr:ident, $htmlname:tt ) => (
+        fn $attr(&self) -> DOMString {
+            use dom::bindings::inheritance::Castable;
+            use dom::element::Element;
+            use dom::node::document_from_node;
+            let element = self.upcast::<Element>();
+            let val = element.get_string_attribute(&atom!($htmlname));
+
+            if val.is_empty() {
+                let doc = document_from_node(self);
+                DOMString::from(doc.url().clone().into_string())
+            } else {
+                val
+            }
+        }
+    );
+);
+
 #[macro_export]
 macro_rules! make_enumerated_getter(
     ( $attr:ident, $htmlname:tt, $default:expr, $(($choices: pat))|+) => (