Autocomplete with OnPush does not open panel properly

[willshowell]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

If the autocomplete's md-options length changes from 0 to n due to options arriving asynchronously, the panel should display even with OnPush.

What is the current behavior?

The panel does not show itself until the user types or refocuses the input.

What are the steps to reproduce?

http://plnkr.co/edit/fWoO47LDbCZFJ9i887jU?p=preview

What is the use-case or motivation for changing an existing behavior?

My options are the result of an ajax request. When they arrive, I want filteredOptions to be recalculated and the autocomplete to reflect it. filteredOptions are recalculated, but the autocomplete panel doesn't show itself.

Other information

If filteredOptions uses .startWith(x) where x.length > 0, it works as expected. It only fails if the initial value is an empty array.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}