feat(ext/fetch): add Headers#getSetCookie (#13542)

Spec change: whatwg/fetch#1346
Tests: web-platform-tests/wpt#31442 (ran against
this PR and they all pass)

---------

Co-authored-by: Bartek Iwańczuk <[email protected]>

Author: lucacasonato

ext/fetch/20_headers.js

@@ -308,6 +308,7 @@ class Headers {
    * @param {string} name
    */
   delete(name) {
+    webidl.assertBranded(this, HeadersPrototype);
     const prefix = "Failed to execute 'delete' on 'Headers'";
     webidl.requiredArguments(arguments.length, 1, prefix);
     name = webidl.converters["ByteString"](name, prefix, "Argument 1");
@@ -333,6 +334,7 @@ class Headers {
    * @param {string} name
    */
   get(name) {
+    webidl.assertBranded(this, HeadersPrototype);
     const prefix = "Failed to execute 'get' on 'Headers'";
     webidl.requiredArguments(arguments.length, 1, prefix);
     name = webidl.converters["ByteString"](name, prefix, "Argument 1");
@@ -345,10 +347,25 @@ class Headers {
     return getHeader(list, name);
   }
 
+  getSetCookie() {
+    webidl.assertBranded(this, HeadersPrototype);
+    const list = this[_headerList];
+
+    const entries = [];
+    for (let i = 0; i < list.length; i++) {
+      if (byteLowerCase(list[i][0]) === "set-cookie") {
+        ArrayPrototypePush(entries, list[i][1]);
+      }
+    }
+
+    return entries;
+  }
+
   /**
    * @param {string} name
    */
   has(name) {
+    webidl.assertBranded(this, HeadersPrototype);
     const prefix = "Failed to execute 'has' on 'Headers'";
     webidl.requiredArguments(arguments.length, 1, prefix);
     name = webidl.converters["ByteString"](name, prefix, "Argument 1");

tools/wpt/expectation.json

@@ -4041,25 +4041,9 @@
         "headers-record.any.worker.html": true,
         "headers-structure.any.worker.html": true,
         "header-setcookie.any.html": [
-          "Headers.prototype.getSetCookie with no headers present",
-          "Headers.prototype.getSetCookie with one header",
-          "Headers.prototype.getSetCookie with one header created from an object",
-          "Headers.prototype.getSetCookie with multiple headers",
-          "Headers.prototype.getSetCookie with an empty header",
-          "Headers.prototype.getSetCookie with two equal headers",
-          "Headers.prototype.getSetCookie ignores set-cookie2 headers",
-          "Headers.prototype.getSetCookie preserves header ordering",
           "Set-Cookie is a forbidden response header"
         ],
         "header-setcookie.any.worker.html": [
-          "Headers.prototype.getSetCookie with no headers present",
-          "Headers.prototype.getSetCookie with one header",
-          "Headers.prototype.getSetCookie with one header created from an object",
-          "Headers.prototype.getSetCookie with multiple headers",
-          "Headers.prototype.getSetCookie with an empty header",
-          "Headers.prototype.getSetCookie with two equal headers",
-          "Headers.prototype.getSetCookie ignores set-cookie2 headers",
-          "Headers.prototype.getSetCookie preserves header ordering",
           "Set-Cookie is a forbidden response header"
         ]
       },
@@ -4890,8 +4874,6 @@
         ]
       },
       "idlharness.any.html": [
-        "Headers interface: operation getSetCookie()",
-        "Headers interface: new Headers() must inherit property \"getSetCookie()\" with the proper type",
         "Request interface: attribute destination",
         "Request interface: attribute referrer",
         "Request interface: attribute referrerPolicy",
@@ -4923,8 +4905,6 @@
         "Window interface: operation fetch(RequestInfo, optional RequestInit)"
       ],
       "idlharness.any.worker.html": [
-        "Headers interface: operation getSetCookie()",
-        "Headers interface: new Headers() must inherit property \"getSetCookie()\" with the proper type",
         "Request interface: attribute destination",
         "Request interface: attribute referrer",
         "Request interface: attribute referrerPolicy",