Reland of Avoid nuking everything when injecting stylesheet.

Reland of Avoid nuking everything when injecting stylesheet. (patchset #1 id:1 of https://codereview.chromium.org/1770903002/ )

Reason for revert:
Relanding since the original CL doesn't seem to be the cause of the flakiness.

Original issue's description:
> Revert of Avoid nuking everything when injecting stylesheet. (patchset #1 id:1 of https://codereview.chromium.org/1762443004/ )
>
> Reason for revert:
> Seems to have introduced a (slightly flaky) use-after-free on Mac ASan 64:
> https://build.chromium.org/p/chromium.memory/builders/Mac%20ASan%2064%20Tests%20%281%29?numbuilds=100
>
> "All_ParameterizedWebFrameTest.SetForceZeroLayoutHeightWorksAcrossNavigations_1" fails pretty consistently (only 1 success out of ~20 runs), a few others fail only occasionally.
>
> Original issue's description:
> > Avoid nuking everything when injecting stylesheet.
> >
> > Instead do an analyzed update of the Document scope.
> >
> > Committed: https://crrev.com/6ddb19de461880fa47a5c563f30119e6d05b20be
> > Cr-Commit-Position: refs/heads/master@{#379528}
>
> TBR=dstockwell@chromium.org,rune@opera.com
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
>
> Committed: https://crrev.com/3b2214c75296d5ee376f7a3853af14ab7aafb98d
> Cr-Commit-Position: refs/heads/master@{#379580}

TBR=dstockwell@chromium.org,rune@opera.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/701f238b27019e76f57af621f52ad7f5a53456d3
Cr-Commit-Position: refs/heads/master@{#379615}

[Marc Treib, 2016-03-07 19:45:54]

Created Reland of Avoid nuking everything when injecting stylesheet.

[commit-bot: I haz the power, 2016-03-07 19:46:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1767163002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1767163002/1

[commit-bot: I haz the power, 2016-03-07 19:47:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-07 19:50:08]

Description was changed from

==========
Reland of Avoid nuking everything when injecting stylesheet. (patchset #1 id:1
of https://codereview.chromium.org/1770903002/ )

Reason for revert:
Relanding since the original CL doesn't seem to be the cause of the flakiness.

Original issue's description:
> Revert of Avoid nuking everything when injecting stylesheet. (patchset #1 id:1
of https://codereview.chromium.org/1762443004/ )
> 
> Reason for revert:
> Seems to have introduced a (slightly flaky) use-after-free on Mac ASan 64:
>
https://build.chromium.org/p/chromium.memory/builders/Mac%20ASan%2064%20Tests...
> 
>
"All_ParameterizedWebFrameTest.SetForceZeroLayoutHeightWorksAcrossNavigations_1"
fails pretty consistently (only 1 success out of ~20 runs), a few others fail
only occasionally.
> 
> Original issue's description:
> > Avoid nuking everything when injecting stylesheet.
> >
> > Instead do an analyzed update of the Document scope.
> >
> > Committed: https://crrev.com/6ddb19de461880fa47a5c563f30119e6d05b20be
> > Cr-Commit-Position: refs/heads/master@{#379528}
> 
> TBR=dstockwell@chromium.org,rune@opera.com
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> 
> Committed: https://crrev.com/3b2214c75296d5ee376f7a3853af14ab7aafb98d
> Cr-Commit-Position: refs/heads/master@{#379580}

TBR=dstockwell@chromium.org,rune@opera.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
==========

to

==========
Reland of Avoid nuking everything when injecting stylesheet. (patchset #1 id:1
of https://codereview.chromium.org/1770903002/ )

Reason for revert:
Relanding since the original CL doesn't seem to be the cause of the flakiness.

Original issue's description:
> Revert of Avoid nuking everything when injecting stylesheet. (patchset #1 id:1
of https://codereview.chromium.org/1762443004/ )
>
> Reason for revert:
> Seems to have introduced a (slightly flaky) use-after-free on Mac ASan 64:
>
https://build.chromium.org/p/chromium.memory/builders/Mac%20ASan%2064%20Tests...
>
>
"All_ParameterizedWebFrameTest.SetForceZeroLayoutHeightWorksAcrossNavigations_1"
fails pretty consistently (only 1 success out of ~20 runs), a few others fail
only occasionally.
>
> Original issue's description:
> > Avoid nuking everything when injecting stylesheet.
> >
> > Instead do an analyzed update of the Document scope.
> >
> > Committed: https://crrev.com/6ddb19de461880fa47a5c563f30119e6d05b20be
> > Cr-Commit-Position: refs/heads/master@{#379528}
>
> TBR=dstockwell@chromium.org,rune@opera.com
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
>
> Committed: https://crrev.com/3b2214c75296d5ee376f7a3853af14ab7aafb98d
> Cr-Commit-Position: refs/heads/master@{#379580}

TBR=dstockwell@chromium.org,rune@opera.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/701f238b27019e76f57af621f52ad7f5a53456d3
Cr-Commit-Position: refs/heads/master@{#379615}
==========

[commit-bot: I haz the power, 2016-03-07 19:50:09]

Patchset 1 (id:??) landed as
https://crrev.com/701f238b27019e76f57af621f52ad7f5a53456d3
Cr-Commit-Position: refs/heads/master@{#379615}