Roll EGL headers. Update CGL backend to use new EGL types. BUG=angleproject:1707 Change-Id: I165e81a758cad0a8036aef68c44a57bcc61e982d Reviewed-on: https://chromium-review.googlesource.com/428292 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>