Refactor ValidateDrawBase. Split the parameter-dependent and parameter-independent validation. This will more easily let us cache independent validation in Context. Bug: angleproject:2747 Change-Id: I78a12798cd03a398392ca213bf51e2079295b97e Reviewed-on: https://chromium-review.googlesource.com/1158610 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Frank Henigman <fjhenigman@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>