diff --git a/components/script/dom/url.rs b/components/script/dom/url.rs
index 35dc4d896fa..dbcefe48e53 100644
--- a/components/script/dom/url.rs
+++ b/components/script/dom/url.rs
@@ -17,10 +17,8 @@ use ipc_channel::ipc;
 use net_traits::{CoreResourceMsg, IpcSend};
 use net_traits::blob_url_store::{get_blob_origin, parse_blob_url};
 use net_traits::filemanager_thread::FileManagerThreadMsg;
-use std::borrow::ToOwned;
 use std::default::Default;
-use url::{Host, Url};
-use url::quirks::domain_to_unicode;
+use url::Url;
 use uuid::Uuid;
 
 // https://url.spec.whatwg.org/#url
@@ -96,23 +94,6 @@ impl URL {
         Ok(result)
     }
 
-    // https://url.spec.whatwg.org/#dom-url-domaintoasciidomain
-    pub fn DomainToASCII(_: &GlobalScope, origin: USVString) -> USVString {
-        // Step 1.
-        let ascii_domain = Host::parse(&origin.0);
-        if let Ok(Host::Domain(string)) = ascii_domain {
-            // Step 3.
-            USVString(string.to_owned())
-        } else {
-            // Step 2.
-            USVString("".to_owned())
-        }
-    }
-
-    pub fn DomainToUnicode(_: &GlobalScope, origin: USVString) -> USVString {
-        USVString(domain_to_unicode(&origin.0))
-    }
-
     // https://w3c.github.io/FileAPI/#dfn-createObjectURL
     pub fn CreateObjectURL(global: &GlobalScope, blob: &Blob) -> DOMString {
         /// XXX: Second field is an unicode-serialized Origin, it is a temporary workaround
diff --git a/components/script/dom/webidls/URL.webidl b/components/script/dom/webidls/URL.webidl
index 738beca4daa..7c47b6caa71 100644
--- a/components/script/dom/webidls/URL.webidl
+++ b/components/script/dom/webidls/URL.webidl
@@ -5,9 +5,6 @@
 // https://url.spec.whatwg.org/#url
 [Constructor(USVString url, optional USVString base), Exposed=(Window,Worker)]
 interface URL {
-  static USVString domainToASCII(USVString domain);
-  static USVString domainToUnicode(USVString domain);
-
   [SetterThrows]
   /*stringifier*/ attribute USVString href;
   readonly attribute USVString origin;
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index bfc8b84612d..2f106202838 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -37715,7 +37715,9 @@
     ]
   },
   "local_changes": {
-    "deleted": [],
+    "deleted": [
+      "url/url-domainToUnicode.html"
+    ],
     "deleted_reftests": {},
     "items": {
       "reftest": {
diff --git a/tests/wpt/web-platform-tests/url/historical.html b/tests/wpt/web-platform-tests/url/historical.html
index 17fdb97294b..fe35b062250 100644
--- a/tests/wpt/web-platform-tests/url/historical.html
+++ b/tests/wpt/web-platform-tests/url/historical.html
@@ -26,4 +26,12 @@ test(function() {
     url.href = "./bar";
   });
 }, "Setting URL's href attribute and base URLs");
+
+test(function() {
+  assert_equals(URL.domainToASCII, undefined);
+}, "URL.domainToASCII should be undefined");
+
+test(function() {
+  assert_equals(URL.domainToUnicode, undefined);
+}, "URL.domainToUnicode should be undefined");
 </script>
diff --git a/tests/wpt/web-platform-tests/url/historical.worker.js b/tests/wpt/web-platform-tests/url/historical.worker.js
index d90915a38a0..ccee73d2ec4 100644
--- a/tests/wpt/web-platform-tests/url/historical.worker.js
+++ b/tests/wpt/web-platform-tests/url/historical.worker.js
@@ -13,4 +13,12 @@ test(function() {
   });
 }, "Setting URL's href attribute and base URLs");
 
+test(function() {
+  assert_equals(URL.domainToASCII, undefined);
+}, "URL.domainToASCII should be undefined");
+
+test(function() {
+  assert_equals(URL.domainToUnicode, undefined);
+}, "URL.domainToUnicode should be undefined");
+
 done();
diff --git a/tests/wpt/web-platform-tests/url/interfaces.html b/tests/wpt/web-platform-tests/url/interfaces.html
index 254242fb884..5d871ad684c 100644
--- a/tests/wpt/web-platform-tests/url/interfaces.html
+++ b/tests/wpt/web-platform-tests/url/interfaces.html
@@ -12,9 +12,6 @@
 [Constructor(USVString url, optional USVString base),
  Exposed=(Window,Worker)]
 interface URL {
-  static USVString domainToASCII(USVString domain);
-  static USVString domainToUnicode(USVString domain);
-
   stringifier attribute USVString href;
   readonly attribute USVString origin;
            attribute USVString protocol;
diff --git a/tests/wpt/web-platform-tests/url/url-domainToUnicode.html b/tests/wpt/web-platform-tests/url/url-domainToUnicode.html
deleted file mode 100644
index 1bd5536799a..00000000000
--- a/tests/wpt/web-platform-tests/url/url-domainToUnicode.html
+++ /dev/null
@@ -1,21 +0,0 @@
-<!doctype html>
-<meta charset="utf-8">
-<title></title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script>
-  test(function() {
-    var domain = 'example.org'
-    assert_true(URL.domainToUnicode(domain) === domain, 'Ascii domain should be parsed correctly.')
-  }, 'URL.domainToUnicode valid input')
-
-  test(function() {
-    var domain = 'xn--maana-pta.com'
-    assert_true(URL.domainToUnicode(domain) === 'mañana.com', ' Ascii encoded domain should be parsed correctly.')
-  }, 'URL.domainToUnicode valid encoded input')
-
-  test(function() {
-    var domain = 'http://not.a.domain'
-    assert_true(URL.domainToUnicode(domain) === "", 'Invalid domain should be return an empty string.')
-  }, 'URL.domainToUnicode invalid input')
-</script>