[Background Sync] Allow sync manager access from uncontrolled clients

LayoutTests/http/tests/background_sync/oneshot.html

Index: LayoutTests/http/tests/background_sync/oneshot.html
diff --git a/LayoutTests/http/tests/background_sync/oneshot.html b/LayoutTests/http/tests/background_sync/oneshot.html
index fd8f698ab06d77ce7ec838519b1dcd1a44ee2ed2..87663fa605934e6ff869de26d4fa917abeda20db 100644
--- a/LayoutTests/http/tests/background_sync/oneshot.html
+++ b/LayoutTests/http/tests/background_sync/oneshot.html
@@ -51,10 +51,37 @@ promise_test(function(t) {
   }, 'Background Sync API should allow one-shot syncs to be registered from ' +
      'the Document scope');
 
-// The test which verified that uncontrolled window clients could not register
-// sync events is out-of-date, and so has been removed. Uncontrolled window
-// clients should be allowed to register sync events, as long as they have a
-// registered service worker.
-// TODO(iclelland): Add a test which verifies the correct behaviour, as per
-// crbug/518884
+promise_test(function(t) {
+  var url = 'resources/empty_worker.js';
+  var scope = 'resources/scope/background_sync/oneshot-uncontrolled.html';
+  var sync_manager;
+  var sync_registration;
+
+  // One-shot syncs can also be registered from uncontrolled documents. This
+  // test creates a frame, after the service worker is active, in order to use
+  // its service worker registration.
+  return service_worker_unregister_and_register(t, url, scope)
+    .then(function(sw_registration) {
+        sync_manager = sw_registration.sync;
+        return wait_for_state(t, sw_registration.installing, 'activated');
+      })
+    .then(function() { return clear_registered_syncs(sync_manager); })
+    .then(function() { return sync_manager.getRegistrations(); })
+    .then(function(registrations) {
+        assert_equals(registrations.length, 0, 'One-shot syncs should be ' +
+                      'cleared at the start of the test.');
+        return sync_manager.register({tag: 'abcde'});
+      })
+    .then(function(registration) {
+        sync_registration = registration;
+        assert_class_string(sync_registration, 'SyncRegistration', 'One-' +
+                            'shot sync registrations should have the correct ' +
+                            'class name.');
+        assert_equals('abcde', registration.tag, 'Sync registration tag ' +
+                      'returned should match the tag registered.');
+        return service_worker_unregister(t, scope);

[jsbell, 2015/09/01 16:25:08]

Just a sanity check since I haven't been following the design of background sync
closely: Will the unregister here ensure that the registered one-shot sync will
never fire? 

(I just want to make sure this won't cause spurious syncs in later tests, since
the test runner's state isn't completely cleared between tests.)

[iclelland, 2015/09/01 16:57:49]

Yes, the BackgroundSyncManager is a ServiceWorkerContextObserver, and it will
clear all registered syncs from its in-memory mapping when the service worker
registration is removed.

+      })
+    .then(function() { return service_worker_unregister(t, scope); })
+  }, 'Background Sync API should allow one-shot syncs to be registered ' +
+     'with window clients not currently controlled by service worker');
 </script>