Generate egl configs from the DisplayImpl. Still do the actual generation in the Renderer9/11 for now but route it through the DisplayImpl. BUG=angle:658 Change-Id: Ib976fbd1b9e349146dc068bbdd4e6a3d2a5ddc69 Reviewed-on: https://chromium-review.googlesource.com/238860 Reviewed-by: Brandon Jones <bajones@chromium.org> Reviewed-by: Kenneth Russell <kbr@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>