Refactor index range calculation in DrawCallParams. BUG=864528 Change-Id: Iac418054ae56a2d9dd277d0474019997aeaa834b Reviewed-on: https://chromium-review.googlesource.com/1163633 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>