Revert of Enable the bootstrap sandbox by default.

Revert of Enable the bootstrap sandbox by default. (patchset #1 id:1 of https://codereview.chromium.org/1372343004/ )

Reason for revert:
Caused performance regressions: https://crbug.com/537680

Original issue's description:
> Reland of Enable the bootstrap sandbox by default. (patchset #1 id:1 of https://codereview.chromium.org/1355043004/ )
>
> Reason for revert:
> Fixed issue that was the cause of the revert, https://crbug.com/534650.
>
> Original issue's description:
> > Revert of Enable the bootstrap sandbox by default. (patchset #3 id:40001 of https://codereview.chromium.org/1352623003/ )
> >
> > Reason for revert:
> > Caused Mac 10.10 layout failures: http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac10.10/builds/4593
> >
> > Original issue's description:
> > > Enable the bootstrap sandbox by default.
> > >
> > > This will place renderer processes under the bootstrap sandbox. This can be
> > > disabled with --disable-bootstrap-sandbox.
> > >
> > > BUG=367863
> > >
> > > Committed: https://crrev.com/2dded5291bc5e9427721e1a06c74f2a80a86e8fa
> > > Cr-Commit-Position: refs/heads/master@{#350006}
> >
> > TBR=avi@chromium.org
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=367863
> >
> > Committed: https://crrev.com/f1422520b42e8fa5b4ffe75359af96bac75d67b0
> > Cr-Commit-Position: refs/heads/master@{#350065}
>
> TBR=avi@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=367863
>
> Committed: https://crrev.com/be226728db60e5860ab8d775eae36e406a41d7ee
> Cr-Commit-Position: refs/heads/master@{#351386}

TBR=avi@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=367863
Committed: https://crrev.com/ce0bd3344168be0edc385c02cb7f0ef393540a1a
Cr-Commit-Position: refs/heads/master@{#351809}

[Robert Sesek, 2015-10-01 15:19:49]

Created Revert of Enable the bootstrap sandbox by default.

[commit-bot: I haz the power, 2015-10-01 15:20:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1379133003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1379133003/1

[commit-bot: I haz the power, 2015-10-01 15:21:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-01 15:21:46]

Patchset 1 (id:??) landed as
https://crrev.com/ce0bd3344168be0edc385c02cb7f0ef393540a1a
Cr-Commit-Position: refs/heads/master@{#351809}