servo: Merge #9518 - Implemented XMLHttpRequest.responseURL (from shinglyu:responseurl); r=jdm

Resolves #8830

Source-Repo: https://github.com/servo/servo
Source-Revision: 50193e9119c567c2c511a53749ff188b9c7ec49e

servo/components/script/dom/xmlhttprequest.rs

@@ -118,7 +118,7 @@ pub struct XMLHttpRequest {
     timeout: Cell<u32>,
     with_credentials: Cell<bool>,
     upload: JS<XMLHttpRequestUpload>,
-    response_url: String,
+    response_url: DOMRefCell<String>,
     status: Cell<u16>,
     status_text: DOMRefCell<ByteString>,
     response: DOMRefCell<ByteString>,
@@ -160,7 +160,7 @@ impl XMLHttpRequest {
             timeout: Cell::new(0u32),
             with_credentials: Cell::new(false),
             upload: JS::from_rooted(&XMLHttpRequestUpload::new(global)),
-            response_url: String::from(""),
+            response_url: DOMRefCell::new(String::from("")),
             status: Cell::new(0),
             status_text: DOMRefCell::new(ByteString::new(vec!())),
             response: DOMRefCell::new(ByteString::new(vec!())),
@@ -691,7 +691,7 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
 
     // https://xhr.spec.whatwg.org/#the-responseurl-attribute
     fn ResponseURL(&self) -> USVString {
-        USVString(self.response_url.clone())
+        USVString(self.response_url.borrow().clone())
     }
 
     // https://xhr.spec.whatwg.org/#the-status-attribute
@@ -876,6 +876,8 @@ impl XMLHttpRequest {
             }
         }
 
+        *self.response_url.borrow_mut() = metadata.final_url.serialize_no_fragment();
+
         // XXXManishearth Clear cache entries in case of a network error
         self.process_partial_response(XHRProgress::HeadersReceived(gen_id,
                                                                    metadata.headers,
@@ -980,6 +982,7 @@ impl XMLHttpRequest {
 
                 // Subsubsteps 5-7
                 self.send_flag.set(false);
+
                 self.change_ready_state(XMLHttpRequestState::Done);
                 return_if_fetch_was_terminated!();
                 // Subsubsteps 10-12