Upstream service wrkr "skipWaiting" tests to WPT

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

 // TODO(nhiroki): stop using global states because service workers can be killed
 // at any point (http://crbug.com/558244).
 self.state = 'starting';
 
 self.addEventListener('install', function() {
     self.state = 'installing';
   });
 
 self.addEventListener('activate', function() {
     self.state = 'activating';
   });
 
 self.addEventListener('message', function(event) {
     var port = event.data.port;
     if (self.state !== 'installing') {
       port.postMessage('FAIL: Worker should be waiting in installed state');
       return;
     }
     event.waitUntil(self.skipWaiting()
       .then(function(result) {
           if (result !== undefined) {
             port.postMessage('FAIL: Promise should be resolved with undefined');
             return;
           }
           if (self.state !== 'activating') {
             port.postMessage(
-                'FAIL: Promise should be resolved after worker activated');
+                'This assertion is invalid. See https://crbug.com/725616');

[falken, 2017/05/29 03:54:17]

I'd be more explicit. The negative asserts in this test are a little confusing:

'This assertion passes in current Chromium (i.e., self.state is 'activating'),
but it should fail. See https://crbug.com/725616'

[mike3, 2017/05/29 15:11:49]

Done.

             return;
           }
           port.postMessage('PASS');
         })
       .catch(function(e) {
           port.postMessage('FAIL: unexpected exception: ' + e);
         }));
   });