This reverts commit fa9b803e.

Reason for revert: https://bugs.chromium.org/p/chromium/issues/detail?id=1157748

Original change's description:
> GLX: Expose EGL_ANGLE_window_fixed_size
>
> Right now the GLX backend checks for resize on every SwapBuffers
> call. If EGL_ANGLE_window_fixed_size is used, it will only resize
> when signaled by Chrome.
>
> Bug: chromium:1132827
> Change-Id: Ia4ddbbbf6dcf13f46ad564208eccc517de8be33c
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2572886
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>

TBR=syoussefi@chromium.org,jonahr@google.com,jmadill@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:1132827
Change-Id: I1110c5dd5d806b3c6c59308d4865f0d3aa57fc3f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2595197Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>