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

LayoutTests/http/tests/serviceworker/resources/fetch-access-control-worker.js

+self.onmessage = function(e) {
+    var message = e.data;
+    if ('port' in message) {
+        port = message.port;
+    }
+};
+
+var baseFrameHtml =
+    '<script>' +
+    'function onMessage(event) {' +
+    '  var script = document.createElement(\'script\');' +
+    '  script.src = event.data.url;' +
+    '  script.addEventListener(' +
+    '      \'error\',' +
+    '      function() {report({jsonpResult:\'error\'})});' +
+    '  document.body.appendChild(script);' +
+    '}' +
+    'function report(data) {' +
+    '  window.parent.postMessage(' +
+    '    data,' +
+    '    \'http://127.0.0.1:8000/serviceworker/fetch-access-control.html\');' +
+    '}' +
+    'function onload() {' +
+    '  window.addEventListener(\'message\', onMessage, false);' +
+    '}' +
+    'window.addEventListener(\'load\', onload);' +
+    '</script>';
+
+function handleFrame(event) {
+    event.respondWith(new Response(new Blob([baseFrameHtml])));
+}
+
+function getQueryParams(url) {
+    var search = (new URL(url)).search;
+    if (!search) {
+        return {};
+    }
+    var ret = {};
+    var params = search.substring(1).split('&');
+    params.forEach(function(param) {
+        var element = param.split('=');
+        ret[decodeURIComponent(element[0])] = decodeURIComponent(element[1]);
+    });
+    return ret;
+}
+
+function getRequestInit(params) {
+    var init = {};
+    if (params['method']) {
+        init['method'] = params['method'];
+    }
+    if (params['mode']) {
+        init['mode'] = params['mode'];
+    }
+    if (params['credentials']) {
+        init['credentials'] = params['credentials'];
+    }
+    if (params['headers'] == 'CUSTOM') {
+        init['headers'] = {"X-ServiceWorker-Test": "test"};
+    } else if (params['headers'] == '{}') {
+        init['headers'] = {};
+    }
+    return init;
+}
+
+function headersToArray(headers) {
+    var ret = [];
+    headers.forEach(function(value, key) {
+        ret.push([key, value]);
+    });
+    return ret;
+}
+
+self.addEventListener('fetch', function(event) {
+    var originalURL = event.request.url;
+    if (originalURL == 'http://127.0.0.1:8000/serviceworker/resources/fetch-access-control-iframe.html') {
+        handleFrame(event);
+    } else {
+        var params = getQueryParams(originalURL);
+        var init =  getRequestInit(params);
+        var url = params['url'];
+        if (params['ignore']) {
+            return;
+        }
+        event.respondWith(new Promise(function(resolve, reject) {
+            try {
+                var request = event.request;
+                if (url) {
+                    request = new Request(url, init);
+                } else if (!params['noChange']) {
+                    request = new Request(request, init);
+                }
+                fetch(request).then(function(res){
+                    // Send the result to fetch-access-control.html.
+                    port.postMessage({fetchResult: 'resolved',
+                                      hasBody: !!res.body,
+                                      headers: headersToArray(res.headers),
+                                      type: res.type,
+                                      originalURL: originalURL});
+                    resolve(res);
+                }).catch(function(e){
+                    // Send the result to fetch-access-control.html.
+                    port.postMessage({fetchResult: 'rejected'});
+                    reject();
+                });
+            } catch (e) {
+                // Send the result to fetch-access-control.html.
+                port.postMessage({fetchResult: 'error'});
+                reject();
+            }
+        }));
+    }
+});