Implement request's redirect mode and RequestRedirect for Fetch

LayoutTests/http/tests/fetch/script-tests/request.js

 if (self.importScripts) {
   importScripts('../resources/fetch-test-helpers.js');
 }
 
 var URL = 'https://www.example.com/test.html';
 
 test(function() {
     var headers = new Headers;
     headers.set('User-Agent', 'Mozilla/5.0');
     headers.set('Accept', 'text/html');
@@ skipping 598 matching lines @@
   }, 'Consume and pass');
 
 // Tests for requests context.
 test(function() {
     var request = new Request('http://localhost/', {method: 'POST', body: ''});
     assert_equals(request.context, '',
                   'Request.context should be empty string ' +
                   'for synthetic Request object');
   }, 'RequestContext of a synthetic Request object');
 
+// Tests for requests redirect mode.
+test(function() {
+    var request1 = {};
+    var REDIRECT = ['follow', 'error'];
+    REDIRECT.forEach(function(redirect1) {
+        var init1 = {};
+        init1['redirect'] = redirect1;
+        request1 = new Request(URL, init1);
+        assert_equals(request1.redirect, redirect1 || 'follow',

[yhirano, 2015/05/25 06:30:52]

What does this "redirect1 || 'follow'" mean?

[shiva.jm, 2015/05/25 12:01:57]

Done.

+                      'Request.redirect should match');
+        request1 = new Request(request1);
+        assert_equals(request1.redirect, redirect1 || 'follow',

[yhirano, 2015/05/25 06:30:52]

ditto

[shiva.jm, 2015/05/25 12:01:56]

Done.

+                      'Request.redirect should match');
+      });
+  }, 'Request redirect mode test');
+
+test(function() {
+    assert_throws(
+      {name: 'TypeError'},
+      function() {
+        new Request('http://localhost/',{method: 'POST', redirect: 'manual'});
+      },
+      'new Request with manual redirect mode should throw');
+
+  }, 'Request redirect with manual mode test');
 done();