ServiceWorker: support Request.{url,method,origin,headers} [blink] (1/3)

LayoutTests/http/tests/serviceworker/resources/request-worker.js

 importScripts('worker-test-helpers.js');
 
 test(function() {
     var headers = new HeaderMap;
-    headers.set('Content-Language', 'ja');
-    headers.set('Content-Type', 'text/html; charset=UTF-8');
-    headers.set('X-ServiceWorker-Test', 'response test field');
+    headers.set('User-Agent', 'Mozilla/5.0');
+    headers.set('Accept', 'text/html');
+    headers.set('X-ServiceWorker-Test', 'request test field');
 
-    var response = new Response({
-        status: 303,
-        statusText: 'See Other',
+    var request = new Request({
+        url: 'https://www.example.com/test.html',
+        method: 'GET',
         headers: headers
     });
 
-    assert_equals(response.status, 303, 'Response.status should match');
-    assert_equals(response.statusText, 'See Other', 'Response.statusText should match');
-    assert_true(response.headers instanceof HeaderMap, 'Response.headers should be HeaderMap');
-    assert_equals(response.headers.size, 3, 'Response.headers.size should match');
+    assert_equals(request.url, 'https://www.example.com/test.html', 'Request.url should match');
+    assert_equals(request.method, 'GET', 'Request.method should match');
+    assert_equals(request.origin, 'https://www.example.com', 'Request.origin should match');
+    assert_true(request.headers instanceof HeaderMap, 'Request.headers should be HeaderMap');
+    assert_equals(request.headers.size, 3, 'Request.headers.size should match');
     // Note: detailed behavioral tests for HeaderMap are in another test,
     // http/tests/serviceworker/headermap.html.
 
-}, 'Response in ServiceWorkerGlobalScope');
+}, 'Request in ServiceWorkerGlobalScope');