_tryExtHostHandshake depends on winjs.promise timing

[jrieken]

This commit 7224bb3 apparently broken debug in weird ways. The $registerDebugTypes was called anymore. This commit fixed it again:
407a485

[alexdima]

How can that break debugging 🦀

[jrieken]

Good question... I was in revert mode only but my theory is that it sends a message before we are ready for it to be processed (it sends something in a ctor-call).

[alexdima]

After some investigation: this is not about the ctor.

TPromise and Promise behave in the same way around the invocation order of the ctor.

The difference is the invocation of then, where Promise always invokes then on the next tick. The result of the promise is an IMessagePassingProtocol and in between those ticks to invoke the then handler, a message (or more) get lost.

I will look into how it would be possible to refactor this... It would almost need pause/resume functionality on IMessagePassingProtocol...