CREDENTIAL: Rework the integration with Fetch (2/2)

third_party/WebKit/LayoutTests/http/tests/credentialmanager/resources/fetch-serviceworker.html

+<script>
+    var c = new PasswordCredential({
+        id: 'id',
+        password: 'pencil',
+        name: 'name',
+        iconURL: 'https://example.com/icon.png'
+    });
+
+    function testServiceWorkerVisibility() {
+        return new Promise((resolve, reject) => {
+            fetch(window.location.pathname + "?respond-with-body", { credentials: c, method: 'POST' })
+                .then(r => r.json())
+                .then(j => {
+                    if (j.credentials != 'password')
+                        reject("Credentials was '" + j.credentials + "'");

[philipj_slow, 2016/04/06 13:33:00]

Since you're using fancy new arrow functions, you may also be interested in
`Credentials was '${j.credentials}'` which is pretty much made for this kind of
situation.

+                    if (j.body != '')
+                        reject("Body was '" + j.body + "'");
+                    resolve();
+                });
+        });
+    }
+
+    function testServiceWorkerNetworkVisibility() {
+        return new Promise((resolve, reject) => {
+            fetch("./echo-post.php", { credentials: c, method: "POST" })
+                .then(r => r.json())
+                .then(j => {
+                    if (j.username != 'id')
+                        reject("Username was '" + j.username + "'");
+                    if (j.password != 'pencil')
+                        reject("Password was '" + j.password + "'");
+                    resolve();
+                });
+        });
+    }

[horo, 2016/04/04 05:32:17]

Please add tests for
1. e.respondWith(fetch(e.request))
2. e.respondWith(fetch(e.request.clone()))

+</script>