[Paginator] Does not update correctly when `pageSize` updated programatically

[girlpunk]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

When changing the pageSize attribute on a pager instance, the pager should immediately redraw the visible rows to match the new setting.

What is the current behavior?

The description text ("Items per page: 10") is updated, however the old number of rows still appear.

What are the steps to reproduce?

https://stackblitz.com/edit/angular-material2-issue-pvrjd5

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

Dynamically changing the number of rows (e.g. on page resize)

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

Angular 6.0.6, Material 6.4.1

Is there anything else we should know?

Calling _changePageSize() instead of changing the property works as expected.

[JayAhn2]

I've got the same issue here... It is quite serious issue for me as I cannot properly control the current state of pagination.