Previously called DrawCallVertexParams. This params helper will be
passed into the VertexArray state sync method so we can handle
vertex attribute updates directly in the VertexArray implementation
instead of deferring the updates to the draw call, where the draw
call implementation method would have access to the draw call params.

Also includes the full range of draw parameters to DrawCallParams so
we can use it in more places.

Refactoring change only, subsequent work will contain more refactoring
and lead to code cleanups and easier dependent state updates for the
VertexArray implementation classes.

Bug: angleproject:2389
Change-Id: Ia84f8af54ae51eca94d8fb6f5b8adc88b8d981a7
Reviewed-on: https://chromium-review.googlesource.com/948787
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>