Fix bugs introduced in ChooserActivity

* Wait to start animations until all state has been initialized, as
  the process of starting an Animator will set initial values,
  triggering other events relying on the configured state.

* Correctly track underlying item indexes for columns.

* Do not over-extend the ResolverDrawerLayout when multiple rows
  animate in.

Bug 24926885
Bug 24928706

Change-Id: I4772e1a0ba79b17b5dc19c778f3ef0cb5200c533