ConnectedPositionStrategy doesn't work properly if the overlay's content is dynamic

[mjamin]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

Position the overlay correctly within the viewport if possible.

What is the current behavior?

Overlay is positioned exceeding the viewport if the overlay's contents are dynamic and there's no fixed width set.

What are the steps to reproduce?

https://plnkr.co/edit/9hUThjYmfC7ofpSBDdKU

If the overlay's content is dynamic, the actual dimensions of the overlay content are set after the positioning logic runs.

Workaround:

setTimeout(() => overlayRef.updatePosition()); // queue update when overlay is shown

Which versions of Angular, Material, OS, browsers are affected?

Angular: 4.0.2
Material: 2.0.0-beta.3