Fix infinite recursion crash in HarfBuzz' CoreText backend

Fix infinite recursion crash in HarfBuzz' CoreText backend

The font cascade reconfiguration which was introduced as fix for AAT
shaping performance regressions in crbug.com/547912 seems to
occasionally cause CoreText crashes on OS X 10.9. We don't have a better
way of detecting this than by OS or CoreText API version number. This is
one of our top Mac crashers on Mac OS 10.9 with Chrome across versions [1].

This crash does not occur in newer versions of OS X and we can keep this
important performance optimization enabled there.

A big thanks to Robert Sesek (rsesek@) for the patient and thorough
initial investigation. Discussing and working together on this issue we
were able to identify the crash triggering code in HarfBuzz in this
case.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=576941#c74

BUG=576941, 625902
Review-Url: https://codereview.chromium.org/2173883002
Cr-Commit-Position: refs/heads/master@{#407185}
(cherry picked from commit 64a2d4d02ea769c849df4718d196df12a3f79091)

Committed: https://chromium.googlesource.com/chromium/src/+/79ae5a3b7fb58358b23443cbd8a3e09087e0ac86

[drott, 2016-07-27 15:36:46]

Description was changed from

==========
Fix infinite recursion crash in HarfBuzz' CoreText backend

The font cascade reconfiguration which was introduced as fix for AAT
shaping performance regressions in crbug.com/547912 seems to
occasionally cause CoreText crashes on OS X 10.9. We don't have a better
way of detecting this than by OS or CoreText API version number. This is
one of our top Mac crashers on Mac OS 10.9 with Chrome across versions [1].

This crash does not occur in newer versions of OS X and we can keep this
important performance optimization enabled there.

A big thanks to Robert Sesek (rsesek@) for the patient and thorough
initial investigation. Discussing and working together on this issue we
were able to identify the crash triggering code in HarfBuzz in this
case.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=576941#c74

BUG=576941, 625902

Review-Url: https://codereview.chromium.org/2173883002
Cr-Commit-Position: refs/heads/master@{#407185}
(cherry picked from commit 64a2d4d02ea769c849df4718d196df12a3f79091)
==========

to

==========
Fix infinite recursion crash in HarfBuzz' CoreText backend

The font cascade reconfiguration which was introduced as fix for AAT
shaping performance regressions in crbug.com/547912 seems to
occasionally cause CoreText crashes on OS X 10.9. We don't have a better
way of detecting this than by OS or CoreText API version number. This is
one of our top Mac crashers on Mac OS 10.9 with Chrome across versions [1].

This crash does not occur in newer versions of OS X and we can keep this
important performance optimization enabled there.

A big thanks to Robert Sesek (rsesek@) for the patient and thorough
initial investigation. Discussing and working together on this issue we
were able to identify the crash triggering code in HarfBuzz in this
case.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=576941#c74

BUG=576941, 625902

Review-Url: https://codereview.chromium.org/2173883002
Cr-Commit-Position: refs/heads/master@{#407185}
(cherry picked from commit 64a2d4d02ea769c849df4718d196df12a3f79091)

Committed:
https://chromium.googlesource.com/chromium/src/+/79ae5a3b7fb58358b23443cbd8a3...
==========

[drott, 2016-07-27 15:36:48]

Committed patchset #1 (id:1) manually as
79ae5a3b7fb58358b23443cbd8a3e09087e0ac86.