Potential fix for flaky TSAN

Potential fix for flaky TSAN

TBR=mtklein@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2084243003

Committed: https://skia.googlesource.com/skia/+/949999d0bbc247906995358a90c4e436e9152de2

[msarett, 2016-06-22 21:55:03]

Description was changed from

==========
Potential fix for flaky TSAN

BUG=skia:
==========

to

==========
Potential fix for flaky TSAN

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2084243003
==========

[msarett, 2016-06-22 21:56:24]

msarett@google.com changed reviewers:
+ mtklein@google.com

[msarett, 2016-06-22 21:56:25]

TSAN is occasionally complaining about this test.

I think this'll fix it.

I also think this might be the cause of those strange
failures that we saw on the NO_SIMD bot awhile back...

[msarett, 2016-06-22 21:56:33]

The CQ bit was checked by msarett@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-06-22 21:56:37]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2084243003/1

[commit-bot: I haz the power, 2016-06-22 22:20:45]

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

[commit-bot: I haz the power, 2016-06-22 22:20:47]

Dry run: This issue passed the CQ dry run.

[msarett, 2016-06-22 22:27:54]

Description was changed from

==========
Potential fix for flaky TSAN

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2084243003
==========

to

==========
Potential fix for flaky TSAN

TBR=mtklein@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2084243003
==========

[msarett, 2016-06-22 22:28:01]

The CQ bit was checked by msarett@google.com

[commit-bot: I haz the power, 2016-06-22 22:28:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2084243003/1

[commit-bot: I haz the power, 2016-06-22 22:29:05]

Description was changed from

==========
Potential fix for flaky TSAN

TBR=mtklein@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2084243003
==========

to

==========
Potential fix for flaky TSAN

TBR=mtklein@google.com
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2084243003

Committed:
https://skia.googlesource.com/skia/+/949999d0bbc247906995358a90c4e436e9152de2
==========

[commit-bot: I haz the power, 2016-06-22 22:29:06]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/949999d0bbc247906995358a90c4e436e9152de2

[mtklein, 2016-06-23 00:51:00]

Yup, yup, SkMatrix4::I() is clearly not thread safe in a world of
-fno-thread-safe-statics.   lgtm.  Don't know if I believe that this explains
the flaky failures, but because nothing else even vaguely explains them, I guess
I have to.

If you're feeling particularly like Doing All The Things, this would be a good
time to explore making some of those SkMatrix44 constructors and factories
constexpr.  Or just deleting SkMatrix44::I().  Or making it return a SkMatrix44
by value.  Or worst case, use SkOnce to initialize the static matrix44 once in a
thread-safe way.

[msarett, 2016-06-23 19:48:29]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2091573004/ by msarett@google.com.

The reason for reverting is: I believe I've fixed SkMatrix44::I() to be thread
safe, let's test it by reverting this CL..