Reland of Add assembly for x86 to OpenH264 encoder (patchset #1 id:1 of https://codereview.chromium.org/2651543002/ )

Reason for revert:
Reland

Original issue's description:
> Revert of Add assembly for x86 to OpenH264 encoder (patchset #5 id:80001 of https://codereview.chromium.org/2585733002/ )
>
> Reason for revert:
> This broke Chrome OS builders:
>
> https://uberchromegw.corp.google.com/i/chromeos/builders/veyron_minnie-chrome-pfq/builds/669/steps/BuildPackages/logs/stdio
>
>
> Original issue's description:
> > Add assembly for x86 to OpenH264 encoder
> >
> > On Linux on a build workstation, these changes seem to give around 2.5x faster encoding (frame encode time in test goes from ~25 to ~9 ms)
> >
> > We do expect alerts from our performance bots when this lands.
> >
> > Credit: These build changes were written by brian@highfive.com aka bbaldino@gmail.com.
> >
> > BUG=600399
> >
> > Review-Url: https://codereview.chromium.org/2585733002
> > Cr-Commit-Position: refs/heads/master@{#445033}
> > Committed: https://chromium.googlesource.com/chromium/src/+/6d1501f500099ff3e25f92593e9efcb27d352252
>
> TBR=kthelgason@chromium.org,ehmaldonado@chromium.org,kthelgason@webrtc.org,hta@chromium.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG=600399
>
> Review-Url: https://codereview.chromium.org/2651543002
> Cr-Commit-Position: refs/heads/master@{#445311}
> Committed: https://chromium.googlesource.com/chromium/src/+/3f4ee1b009741853987773717ebc2f22c5f0c60b

BUG=600399

Review-Url: https://codereview.chromium.org/2645293002
Cr-Commit-Position: refs/heads/master@{#445358}
1 file changed