ServiceWorker: Add support for .skipWaiting and controllerchange event(1/3)

LayoutTests/http/tests/serviceworker/resources/skip-waiting-worker.js

+importScripts('worker-testharness.js');
+
+promise_test(function() {
+    return self.skipWaiting()
+      .then(function(result) {
+          assert_equals(result, undefined,
+                        'Promise should be resolved with undefined');
+        })
+      .then(function() {
+          var num = 8;
+          var promises = [];
+          for (var i = 0; i < num; ++i)
+            promises.push(skipWaiting());
+          return Promise.all(promises)
+            .then(function(results) {
+                assert_equals(results.length, num,
+                              'All promises should be resolved');

[falken, 2014/12/01 02:28:48]

Remove this assert. It's just testing the generic behavior of Promise.all.

[xiang, 2014/12/01 07:13:44]

Done.

+                results.forEach(function(r) {
+                    assert_equals(r, undefined,
+                                  'Promises should be resolved with undefined');
+                  });
+              });
+        });
+  }, 'skipWaiting');