Add location_url to Metadata struct

components/constellation/network_listener.rs

@@ -103,6 +103,7 @@ impl NetworkListener {
 
                         self.res_init = Some(ResponseInit {
                             url: metadata.final_url.clone(),
+                            location_url: metadata.location_url.clone(),
                             headers: headers.clone().into_inner(),
                             referrer: metadata.referrer.clone(),
                         });

components/net_traits/lib.rs

@@ -411,6 +411,9 @@ pub struct Metadata {
     /// Final URL after redirects.
     pub final_url: ServoUrl,
 
+    /// Location URL from the response headers.
+    pub location_url: Option<Result<ServoUrl, String>>,
+
     #[ignore_heap_size_of = "Defined in hyper"]
     /// MIME type / subtype.
     pub content_type: Option<Serde<ContentType>>,
@@ -440,6 +443,7 @@ impl Metadata {
     pub fn default(url: ServoUrl) -> Self {
         Metadata {
             final_url: url,
+            location_url: None,
             content_type: None,
             charset: None,
             headers: None,

components/net_traits/response.rs

@@ -82,6 +82,7 @@ pub struct ResponseInit {
     #[ignore_heap_size_of = "Defined in hyper"]
     pub headers: Headers,
     pub referrer: Option<ServoUrl>,
+    pub location_url: Option<Result<ServoUrl, String>>,
 }
 
 /// A [Response](https://fetch.spec.whatwg.org/#concept-response) as defined by the Fetch spec
@@ -138,6 +139,7 @@ impl Response {
 
     pub fn from_init(init: ResponseInit) -> Response {
         let mut res = Response::new(init.url);
+        res.location_url = init.location_url;
         res.headers = init.headers;
         res.referrer = init.referrer;
         res
@@ -287,6 +289,7 @@ impl Response {
                 Some(&ContentType(ref mime)) => Some(mime),
                 None => None,
             });
+            metadata.location_url = response.location_url.clone();
             metadata.headers = Some(Serde(response.headers.clone()));
             metadata.status = response.raw_status.clone();
             metadata.https_state = response.https_state;