Implement ServiceWorkerClient attributes [3/3]

LayoutTests/http/tests/serviceworker/resources/clients-getall-worker.js

+self.onmessage = function(e) {
+  var port = e.data.port;
+
+  self.clients.getAll().then(function(clients) {
+      var message = [];
+      clients.forEach(function(client) {
+          message.push([client.visibilityState,
+                        client.focused,
+                        client.url,
+                        client.frameType]);
+        });
+      // Sort by url
+      message.sort(function(a, b) { return a[2] > b[2] ? 1 : -1; });
+      port.postMessage(message);
+    });
+};