[ServiceWorker] Make fetch() method better conformance with the spec.

LayoutTests/http/tests/serviceworker/resources/fetch-access-control.php

+<?php
+header('X-ServiceWorker-ServerHeader: SetInTheServer');
+if (isset($_GET['ACAOrigin'])) {
+    $origins = explode(',', $_GET['ACAOrigin']);
+    for ($i = 0; $i < sizeof($origins); ++$i)
+        header("Access-Control-Allow-Origin: " . $origins[$i], false);
+}
+
+if (isset($_GET['ACAHeaders']))
+    header("Access-Control-Allow-Headers: {$_GET['ACAHeaders']}");
+if (isset($_GET['ACAMethods']))
+    header("Access-Control-Allow-Methods: {$_GET['ACAMethods']}");
+if (isset($_GET['ACACredentials']))
+    header("Access-Control-Allow-Credentials: {$_GET['ACACredentials']}");
+if (isset($_GET['ACEHeaders']))
+    header("Access-Control-Expose-Headers: {$_GET['ACEHeaders']}");
+
+if ((isset($_GET['Auth']) and !isset($_SERVER['PHP_AUTH_USER'])) || isset($_GET['AuthFail'])) {
+    header('WWW-Authenticate: Basic realm="Restricted"');
+    header('HTTP/1.0 401 Unauthorized');
+    echo 'Authentication canceled';
+    exit;
+}
+
+$username = 'undefined';
+$password = 'undefined';
+if (isset($_SERVER['PHP_AUTH_USER'])) {
+    $username = $_SERVER['PHP_AUTH_USER'];
+}
+if (isset($_SERVER['PHP_AUTH_PW'])) {
+    $password = $_SERVER['PHP_AUTH_PW'];
+}
+
+header('Content-Type: application/json');
+$arr = array('jsonpResult' => 'success',
+             'method' => $_SERVER['REQUEST_METHOD'],
+             'headers' => getallheaders(),
+             'username' => $username,
+             'password' => $password);
+$json = json_encode($arr);
+echo "report( $json );";
+?>