Bug 1557294 [wpt PR 17204] - Ship `referer` header length limitation., a=testonly

Automatic update from web-platform-tests
Ship `referer` header length limitation. (#17204)

This patch adds web platform tests to verify the behavior of the
referrer header and `document.referrer` after flipping the length
limitiation flag to on-by-default.

Intent to Ship: https://groups.google.com/a/chromium.org/forum/#!msg/blink-dev/lckJ5OAkUNo/ooVNdvhLAgAJ

Bug: 959757
Change-Id: I385f8f12f20109c50ededb9018a08cd665cb6868
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1646784
Commit-Queue: Mike West <mkwst@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667039}
--

wpt-commits: 9e059910c901218756454b7979c6f95a6f306854
wpt-pr: 17204

testing/web-platform/tests/referrer-policy/generic/referrer-policy-test-case.sub.js

@@ -125,14 +125,52 @@ function ReferrerPolicyTestCase(scenario, testDescription, sanityChecker) {
       policyDeliveries: [delivery]
     };
 
+    let currentURL = location.toString();
     const expectedReferrer =
-      referrerUrlResolver[scenario.referrer_url](location.toString());
+      referrerUrlResolver[scenario.referrer_url](currentURL);
 
     // Request in the top-level document.
     promise_test(_ => {
+      return invokeRequest(subresource, [])
+        .then(result => checkResult(expectedReferrer, result));
+    }, testDescription);
+
+    // `Referer` headers with length over 4k are culled down to an origin, so, let's test around
+    // that boundary for tests that would otherwise return the complete URL.
+    if (scenario.referrer_url == "stripped-referrer") {
+      promise_test(_ => {
+        history.pushState(null, null, "/");
+        history.replaceState(null, null, "A".repeat(4096 - location.href.length - 1));
+        const expectedReferrer = location.href;
+        // Ensure that we don't load the same URL as the previous test.
+        subresource.url += "&-1";
         return invokeRequest(subresource, [])
-          .then(result => checkResult(expectedReferrer, result));
-      }, testDescription);
+          .then(result => checkResult(location.href, result))
+          .finally(_ => history.back());
+      }, "`Referer` header with length < 4k is not stripped to an origin.");
+
+      promise_test(_ => {
+        history.pushState(null, null, "/");
+        history.replaceState(null, null, "A".repeat(4096 - location.href.length));
+        const expectedReferrer = location.href;
+        // Ensure that we don't load the same URL as the previous test.
+        subresource.url += "&0";
+        return invokeRequest(subresource, [])
+          .then(result => checkResult(expectedReferrer, result))
+          .finally(_ => history.back());
+      }, "`Referer` header with length == 4k is not stripped to an origin.");
+
+      promise_test(_ => {
+        const originString = referrerUrlResolver["origin"](currentURL);
+        history.pushState(null, null, "/");
+        history.replaceState(null, null, "A".repeat(4096 - location.href.length + 1));
+        // Ensure that we don't load the same URL as the previous test.
+        subresource.url += "&+1";
+        return invokeRequest(subresource, [])
+          .then(result => checkResult(originString, result))
+          .finally(_ => history.back());
+      }, "`Referer` header with length > 4k is stripped to an origin.");
+    }
 
     // We test requests from inside iframes only for <img> tags.
     // This is just to preserve the previous test coverage.