| Test cross-frame MessagePort communication. | |
| Should be a series of SUCCESS messages, followed with DONE. | |
| Simple exchange: SUCCESS | |
| Simple exchange: SUCCESS | |
| Posted port: SUCCESS | |
| Posted port: SUCCESS | |
| Event Listener: SUCCESS | |
| Event Listener: SUCCESS | |
| Closed port: SUCCESS | |
| Closed port: SUCCESS | |
| MessageEvent.cancelable defaults to false: PASS | |
| MessageEvent.cancelable defaults to false: PASS | |
| DONE | |