Don't store Renderer in RenderStateCache. Instead pass it around via methods. This makes the code a bit nicer. BUG=angleproject:2044 Change-Id: I721e190a2ecde2b1a65e57debf419ee06a5dce29 Reviewed-on: https://chromium-review.googlesource.com/516385 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org>