This allow for better code reuse for the Indirect draw calls.
It also cleans up the InputLayoutCache to be only responsible
for caching input layouts, and moves the logic for maintaining
state into StateManager11.

Bug: angleproject:2389
Change-Id: I84aae164bf1b94a394743cf58650adfdcfc2c17a
Reviewed-on: https://chromium-review.googlesource.com/948796
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>