ServiceWorker: Support SWRegistration.unregister() in SWGlobalScope [2/2]

LayoutTests/http/tests/serviceworker/ServiceWorkerGlobalScope/resources/unregister-worker.js

+function matchQuery(query) {
+  return self.location.href.indexOf(query) != -1;
+}
+
+if (matchQuery('?evaluation'))
+  self.registration.unregister();
+
+self.addEventListener('install', function(e) {
+    if (matchQuery('?install'))
+      self.registration.unregister();
+  });
+
+self.addEventListener('activate', function(e) {
+    if (matchQuery('?activate'))
+      self.registration.unregister();
+  });
+
+self.addEventListener('message', function(e) {
+    self.registration.unregister()
+      .then(function(result) {
+          e.data.port.postMessage({result: result});
+        });
+  });