Support primitive restart in RendererGL. Store index ranges in a new struct that tracks how many real indices were seen. Update index caching to key on primitive restart being enabled and update index counting functions to skip primitive restart indicies when needed. Passes dEQP-GLES3.functional.primitive_restart.* Change-Id: Id1e25a5adcdcd4e998836e8ff6679c64be4c3066 Reviewed-on: https://chromium-review.googlesource.com/297770 Tryjob-Request: Geoff Lang <geofflang@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>