With the invariant handling changes, we're also exporting gl_Position and other builtin variables from the translator where we were not previously. This was causing an assert in the XFB code, where we would inadvertently assign a register to gl_Position, and trip up logic further in the varying handling logic. BUG=angle:808 Change-Id: I674902da75c572e969f9516033a85c7a7170d7d1 Reviewed-on: https://chromium-review.googlesource.com/225261Reviewed-by: Shannon Woods <shannonwoods@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>
