Cherry pick disabled unicode compatibility decomposition into HarfBuzz

Cherry pick disabled unicode compatibility decomposition into HarfBuzz

HarfBuzz commit f6799700404c49ae0 disables unicode compatibility
decomposition, avoiding undesirable substitutions and allowing Blink
to fall back to system fonts for mathematical symbols and the
like. Cherry-picking this into our HarfBuzz version in order to be able
to land shaper driven segmentation.

BUG=546454
R=behdad,eae

Committed: https://crrev.com/c6da2801d9e36a9f2bb5acf4e3c492c8f0680ad4
Cr-Commit-Position: refs/heads/master@{#355551}

[drott, 2015-10-22 08:29:13]

behdad@ do you think we can cherry-pick this or should we wait for work on
https://github.com/behdad/harfbuzz/issues/153 "Handle space fallback"?

[drott, 2015-10-22 15:00:49]

The CQ bit was checked by drott@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-10-22 15:02:04]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1416013004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1416013004/1

[commit-bot: I haz the power, 2015-10-22 15:55:54]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-10-22 15:55:56]

Dry run: This issue passed the CQ dry run.

[behdad, 2015-10-22 16:33:29]

lgtm

[drott, 2015-10-22 16:36:23]

Description was changed from

==========
Cherry pick disabled unicode compatibility decomposition into HarfBuzz

HarfBuzz commit f6799700404c49ae0 disables unicode compatibility
decomposition, avoiding undesirable substitutions and preventing Blink
from falling back to system fonts for mathematical symbols and the
like. Cherry-picking this into our HarfBuzz version in order to be able
to land shaper driven segmentation.

BUG=546454
R=behdad,eae
==========

to

==========
Cherry pick disabled unicode compatibility decomposition into HarfBuzz

HarfBuzz commit f6799700404c49ae0 disables unicode compatibility
decomposition, avoiding undesirable substitutions and allowing Blink
from falling back to system fonts for mathematical symbols and the
like. Cherry-picking this into our HarfBuzz version in order to be able
to land shaper driven segmentation.

BUG=546454
R=behdad,eae
==========

[drott, 2015-10-22 16:36:39]

Description was changed from

==========
Cherry pick disabled unicode compatibility decomposition into HarfBuzz

HarfBuzz commit f6799700404c49ae0 disables unicode compatibility
decomposition, avoiding undesirable substitutions and allowing Blink
from falling back to system fonts for mathematical symbols and the
like. Cherry-picking this into our HarfBuzz version in order to be able
to land shaper driven segmentation.

BUG=546454
R=behdad,eae
==========

to

==========
Cherry pick disabled unicode compatibility decomposition into HarfBuzz

HarfBuzz commit f6799700404c49ae0 disables unicode compatibility
decomposition, avoiding undesirable substitutions and allowing Blink
to fall back to system fonts for mathematical symbols and the
like. Cherry-picking this into our HarfBuzz version in order to be able
to land shaper driven segmentation.

BUG=546454
R=behdad,eae
==========

[drott, 2015-10-22 16:36:46]

The CQ bit was checked by drott@chromium.org

[commit-bot: I haz the power, 2015-10-22 16:37:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1416013004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1416013004/1

[commit-bot: I haz the power, 2015-10-22 16:41:24]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-22 16:42:16]

Patchset 1 (id:??) landed as
https://crrev.com/c6da2801d9e36a9f2bb5acf4e3c492c8f0680ad4
Cr-Commit-Position: refs/heads/master@{#355551}

[Justin Novosad, 2015-10-22 20:46:44]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1409993005/ by junov@chromium.org.

The reason for reverting is: This change is causing bllink layout test failures
on multiple platforms. Judging from the diffs, this looks like a regression, not
just something that needs rebaselining.

fast/text/unicode-fallback-font.html (windows only)
fast/text/midword-break-before-surrogate-pair.html (windows only)
svg/text/non-bmp-positioning-lists.svg

Affected platforms: 
Mac 10.6 only
Win XP, 7 and 10
Linux 64, 32 and Trusty.