Reland of ix getComputedStyle positioned element values (patchset #2 id:250001 of https://codereview.chromium.org/1888533002/ )

Reason for revert:
The bug is actually caused by scripts depending on old 'auto' value.
Revert the bad revert. Sorry for the noise.

Original issue's description:
> Revert of fix getComputedStyle positioned element values (patchset #4 id:60001 of https://codereview.chromium.org/1826423003/ )
>
> Reason for revert:
> Caused crbug.com/602934.
>
> BUG=602934,589347
>
> Original issue's description:
> > getComputedStyle now returns used values for top, left, bottom, right
> >
> > getComputedStyle now returns used values for the top, left, bottom, and
> > right properties of positioned elements, instead of returning computed
> > values, if the display property is not None.
> >
> > R=mstensho@opera.com
> > BUG=589347
> >
> > Committed: https://crrev.com/6a2ed97b65b691947eeffbf44ff48a8af2ddff3a
> > Cr-Commit-Position: refs/heads/master@{#385493}
>
> TBR=mstensho@opera.com,rune@opera.com,timloh@chromium.org,khart@codeaurora.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG=589347
>
> Committed: https://crrev.com/f119da74988bf022c2dab4193ed289c988d51a26
> Cr-Commit-Position: refs/heads/master@{#387068}

TBR=mstensho@opera.com,rune@opera.com,timloh@chromium.org,khart@codeaurora.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=602934,589347

Review URL: https://codereview.chromium.org/1890743002

Cr-Commit-Position: refs/heads/master@{#387246}
12 files changed