Refactor Texture::syncState to pass down the Context Also returning a gl::Error everywhere. Bug: angleproject:2478 Change-Id: Ic8cae0ee7aee318bb95b3588044c34c62707b578 Reviewed-on: https://chromium-review.googlesource.com/1020083 Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Luc Ferron <lucferron@chromium.org>