ServiceWorker: Enable ServiceWorkerRegistration and update layout tests

LayoutTests/http/tests/serviceworker/chromium/service-worker-gc.html

Index: LayoutTests/http/tests/serviceworker/chromium/service-worker-gc.html
diff --git a/LayoutTests/http/tests/serviceworker/chromium/service-worker-gc.html b/LayoutTests/http/tests/serviceworker/chromium/service-worker-gc.html
index 18e09f603fb74b31cb7594bc4af669a5cb0de62f..aa4176bf71892ab3650d58e1084b68ad191274f8 100644
--- a/LayoutTests/http/tests/serviceworker/chromium/service-worker-gc.html
+++ b/LayoutTests/http/tests/serviceworker/chromium/service-worker-gc.html
@@ -27,7 +27,14 @@ function unregisterAndRegister(url, scope) {
     });
 }
 
-function onRegister(sw) {
+function onRegister(registration) {
+    registrationObservation = internals.observeGC(registration);

[falken, 2014/08/14 04:46:11]

observeGC just returns an observer you can use to check if something was gc'd.
But registrationObservation is not used.

When the ActiveDOMObject change for SWRegistration goes in, we'll want a test
for registration gc. Something like:

register().then(function(r) {
  observation = internals.observeGC(r);
  setTimeout(check, 0);
});

function check() {
  gc();
  shouldBeFalse('observation.wasCollected');
}

If you just want to add to this test, you can check
shouldBeFalse('registrationObservation.wasCollected') after the gc() calls
below.

[horo, 2014/08/14 07:11:46]

Done.

+    registration.addEventListener('updatefound', (function() {
+        onUpdate(registration.installing);
+    }));
+}
+
+function onUpdate(sw) {
     swObservation = internals.observeGC(sw);
     sw.addEventListener('statechange', onStateChange);
 }