Move the EGL-based initial state to the gl::State constructor. This is a small refactor to allow State::initialize to be called without needing the EGL context creation attributes. BUG=angleproject:2464 Change-Id: Ifa167cc83f652435ecc00a0a73e4c6c4a3295430 Reviewed-on: https://chromium-review.googlesource.com/1083312 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>