Import //fetch from Web Platform Tests.

third_party/WebKit/LayoutTests/external/wpt/fetch/api/basic/referrer.js

+if (this.document === undefined) {
+    importScripts("/resources/testharness.js");
+    importScripts("../resources/utils.js");
+    importScripts("/common/get-host-info.sub.js")
+}
+
+function runTest(url, init, expectedReferrer, title) {
+    promise_test(function(test) {
+        url += (url.indexOf('?') !== -1 ? '&' : '?') + "headers=referer&cors";
+
+        return fetch(url , init).then(function(resp) {
+            assert_equals(resp.status, 200, "HTTP status is 200");
+            assert_equals(resp.headers.get("x-request-referer"), expectedReferrer, "Request's referrer is correct");
+        });
+    }, title);
+}
+
+var fetchedUrl = RESOURCES_DIR + "inspect-headers.py";
+var corsFetchedUrl = get_host_info().HTTP_REMOTE_ORIGIN  + dirname(location.pathname) + RESOURCES_DIR + "inspect-headers.py";
+var redirectUrl = RESOURCES_DIR + "redirect.py?location=" ;
+var corsRedirectUrl = get_host_info().HTTP_REMOTE_ORIGIN + dirname(location.pathname) + RESOURCES_DIR + "redirect.py?location=";
+
+runTest(fetchedUrl, { referrerPolicy: "origin-when-cross-origin"}, location.toString(), "origin-when-cross-origin policy on a same-origin URL");
+runTest(corsFetchedUrl, { referrerPolicy: "origin-when-cross-origin"}, get_host_info().HTTP_ORIGIN + "/", "origin-when-cross-origin policy on a cross-origin URL");
+runTest(redirectUrl + corsFetchedUrl, { referrerPolicy: "origin-when-cross-origin"}, get_host_info().HTTP_ORIGIN + "/", "origin-when-cross-origin policy on a cross-origin URL after same-origin redirection");
+runTest(corsRedirectUrl + fetchedUrl, { referrerPolicy: "origin-when-cross-origin"}, get_host_info().HTTP_ORIGIN + "/", "origin-when-cross-origin policy on a same-origin URL after cross-origin redirection");
+
+
+var referrerUrlWithCredentials = get_host_info().HTTP_ORIGIN.replace("http://", "http://username:password@");
+runTest(fetchedUrl, {referrer: referrerUrlWithCredentials}, get_host_info().HTTP_ORIGIN + "/", "Referrer with credentials should be stripped");
+var referrerUrlWithFragmentIdentifier = get_host_info().HTTP_ORIGIN + "#fragmentIdentifier";
+runTest(fetchedUrl, {referrer: referrerUrlWithFragmentIdentifier}, get_host_info().HTTP_ORIGIN + "/", "Referrer with fragment ID should be stripped");
+
+done();
+