Implement request's redirect mode and RequestRedirect for Fetch

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

 if (self.importScripts) {
   importScripts('../resources/fetch-test-helpers.js');
 }
 
 sequential_promise_test(function(t) {
     return fetch('http://')
       .then(
         t.unreached_func('fetch of invalid URL must fail'),
         function() {});
   }, 'Fetch invalid URL');
@@ skipping 38 matching lines @@
 
 sequential_promise_test(function(t) {
     var request = new Request(
       '/serviceworker/resources/fetch-status.php?status=200#fragment');
 
     // The url attribute's getter must return request's url,
     // serialized with the exclude fragment flag set.
     assert_equals(request.url,
       BASE_ORIGIN + '/serviceworker/resources/fetch-status.php?status=200');
     assert_equals(request.context, '');
+    assert_equals(request.redirect, 'follow');
 
     return fetch(request)
       .then(function(response) {
           assert_equals(response.status, 200);
           assert_equals(response.statusText, 'OK');
           // The url attribute's getter must return the empty string
           // if response's url is null and response's url,
           // serialized with the exclude fragment flag set, otherwise.
           assert_equals(response.url,
             BASE_ORIGIN +
             '/serviceworker/resources/fetch-status.php?status=200');
           assert_equals(request.context, '');
+          assert_equals(request.redirect, 'follow');
         });
   }, 'Request/response url attribute getter with fragment');
 
 sequential_promise_test(function(t) {
     var redirect_target_url =
       BASE_ORIGIN + '/serviceworker/resources/fetch-status.php?status=200';
     var redirect_original_url =
       BASE_ORIGIN + '/serviceworker/resources/redirect.php?Redirect=' +
       redirect_target_url;
 
     var request = new Request(redirect_original_url);
     assert_equals(request.url, redirect_original_url,
       'Request\'s url is the original URL');
     assert_equals(request.context, '');
+    assert_equals(request.redirect, 'follow');
 
     return fetch(request)
       .then(function(response) {
           assert_equals(response.status, 200);
           assert_equals(response.statusText, 'OK');
           assert_equals(response.url, redirect_target_url,
             'Response\'s url is locationURL');
           assert_equals(request.url, redirect_original_url,
             'Request\'s url remains the original URL');
           assert_equals(request.context, '');
+          assert_equals(request.redirect, 'follow');
         });
   }, 'Request/response url attribute getter with redirect');
 
 function evalJsonp(text) {
   return new Promise(function(resolve) {
       var report = resolve;
       // text must contain report() call.
       eval(text);
     });
 }
 
 sequential_promise_test(function(t) {
     var request =
       new Request('/serviceworker/resources/fetch-access-control.php',
                   {
                     method: 'POST',
                     body: new Blob(['Test Blob'], {type: 'test/type'})
                   });
     assert_equals(request.context, '');
+    assert_equals(request.redirect, 'follow');
     return fetch(request)
       .then(function(response) { return response.text(); })
       .then(evalJsonp)
       .then(function(result) {
           assert_equals(result.method, 'POST');
           assert_equals(result.body, 'Test Blob');
           assert_equals(request.context, '');
+          assert_equals(request.redirect, 'follow');
         });
   }, 'Fetch with Blob body test');
 
 sequential_promise_test(function(t) {
     var request = new Request(
       '/serviceworker/resources/fetch-access-control.php',
       {method: 'POST', body: 'Test String'});
     return fetch(request)
       .then(function(response) { return response.text(); })
       .then(evalJsonp)
@@ skipping 72 matching lines @@
       fetch('dummy.html')
         .then(function() { runInfiniteFetchLoop(); });
     }
     runInfiniteFetchLoop();
   },
   'Destroying the execution context while fetch is happening should not ' +
   'cause a crash.');
 
 sequential_promise_test_done();
 done();