Remove batching and streaming from the input dispatcher.

Don't worry, these features will be moving to a different part of
the pipeline.  We're just getting them out of the way for now so
we can make deeper changes to how the input dispatcher works.

This is part of a series of changes to improve input system pipelining.

Bug: 5963420

Change-Id: If97de923c8165776882eef23f5204cc448dad0fc