Add GL_OES_draw_texture stubs. BUG=18381077 Change-Id: I0dcb76e7662da6f1c38eeeca75e24a702da28abd Reviewed-on: https://swiftshader-review.googlesource.com/1400 Reviewed-by: Nicolas Capens <nicolascapens@google.com> Tested-by: Nicolas Capens <nicolascapens@google.com>