Don't use ServiceWorkerContainer.unregister in service_worker_unregister_and_register

LayoutTests/http/tests/serviceworker/serviceworkerobject-scripturl.html

Index: LayoutTests/http/tests/serviceworker/serviceworkerobject-scripturl.html
diff --git a/LayoutTests/http/tests/serviceworker/serviceworkerobject-scripturl.html b/LayoutTests/http/tests/serviceworker/serviceworkerobject-scripturl.html
index 1a0771a01cf4fb7f039611da250c251e30b6a826..198678612fbcc1887a5caaef5d696f0769435f26 100644
--- a/LayoutTests/http/tests/serviceworker/serviceworkerobject-scripturl.html
+++ b/LayoutTests/http/tests/serviceworker/serviceworkerobject-scripturl.html
@@ -6,7 +6,7 @@
 <script>
 
 function url_test(name, url) {
-  var scope = '';
+  var scope = 'scope/' + name;
   async_test(function(t) {
     var expectedURL = normalizeURL(url);
     service_worker_unregister_and_register(t, url, scope)
@@ -23,7 +23,7 @@ function url_test(name, url) {
 }
 
 url_test('relative', 'resources/worker-no-op.js');
-url_test('with fragment', 'resources/worker-no-op.js#ref');
+url_test('with-fragment', 'resources/worker-no-op.js#ref');

[falken, 2014/08/15 12:17:08]

Somehow this patch tickled the flakiness you probably were seeing in
https://codereview.chromium.org/466723002/

I think the problem is the different async tests use the same scope, so they run
concurrently mixing each other up.

[nhiroki, 2014/08/18 01:33:17]

Acknowledged.

 url_test('absolute',
          'http://127.0.0.1:8000/serviceworker/resources/worker-no-op.js');