Reland of SkOncePtr -> SkOnce

Reland of SkOncePtr -> SkOnce (patchset #1 id:1 of https://codereview.chromium.org/1945293004/ )

Reason for revert:
previous revert unneeded (I think)

Original issue's description:
> Revert of SkOncePtr -> SkOnce (patchset #4 id:60001 of https://codereview.chromium.org/1953533002/ )
> 
> Reason for revert:
> broken the Mac and Linux builders, e.g.:
> 
> https://build.chromium.org/p/chromium/builders/Mac/builds/15151
> https://build.chromium.org/p/chromium/builders/Linux%20x64/builds/19052
> 
> Original issue's description:
> > SkOncePtr -> SkOnce
> > 
> > It's always nice to kill off a synchronization primitive.
> > And while less terse, I think this new code reads more clearly.
> > 
> > ... and, SkOncePtr's tests were the only thing now using sk_num_cores()
> > outside of SkTaskGroup, so I've hidden it as static inside SkTaskGroup.cpp.
> > 
> > BUG=skia:
> > GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1953533002
> > CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
> > 
> > Committed: https://skia.googlesource.com/skia/+/9bd3fc7fa9bb7cad050bd619aa93d4c48ebb5c02
> 
> TBR=herb@google.com,mtklein@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=skia:
> 
> Committed: https://skia.googlesource.com/skia/+/7eb33da7eede34c050b865dbb1b60c3dcea7191b

TBR=herb@google.com,mtklein@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Committed: https://skia.googlesource.com/skia/+/82da9a8aa0ce648f36882830765b42e0ada6c0fa

[reed1, 2016-05-05 08:28:41]

Created Reland of SkOncePtr -> SkOnce

[commit-bot: I haz the power, 2016-05-05 08:28:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1949313003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1949313003/1

[commit-bot: I haz the power, 2016-05-05 08:29:00]

Description was changed from

==========
Reland of SkOncePtr -> SkOnce (patchset #1 id:1 of
https://codereview.chromium.org/1945293004/ )

Reason for revert:
previous revert unneeded (I think)

Original issue's description:
> Revert of SkOncePtr -> SkOnce (patchset #4 id:60001 of
https://codereview.chromium.org/1953533002/ )
> 
> Reason for revert:
> broken the Mac and Linux builders, e.g.:
> 
> https://build.chromium.org/p/chromium/builders/Mac/builds/15151
> https://build.chromium.org/p/chromium/builders/Linux%20x64/builds/19052
> 
> Original issue's description:
> > SkOncePtr -> SkOnce
> > 
> > It's always nice to kill off a synchronization primitive.
> > And while less terse, I think this new code reads more clearly.
> > 
> > ... and, SkOncePtr's tests were the only thing now using sk_num_cores()
> > outside of SkTaskGroup, so I've hidden it as static inside SkTaskGroup.cpp.
> > 
> > BUG=skia:
> > GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
> >
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
> > 
> > Committed:
https://skia.googlesource.com/skia/+/9bd3fc7fa9bb7cad050bd619aa93d4c48ebb5c02
> 
> TBR=herb@google.com,mtklein@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=skia:
> 
> Committed:
https://skia.googlesource.com/skia/+/7eb33da7eede34c050b865dbb1b60c3dcea7191b

TBR=herb@google.com,mtklein@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:
==========

to

==========
Reland of SkOncePtr -> SkOnce (patchset #1 id:1 of
https://codereview.chromium.org/1945293004/ )

Reason for revert:
previous revert unneeded (I think)

Original issue's description:
> Revert of SkOncePtr -> SkOnce (patchset #4 id:60001 of
https://codereview.chromium.org/1953533002/ )
> 
> Reason for revert:
> broken the Mac and Linux builders, e.g.:
> 
> https://build.chromium.org/p/chromium/builders/Mac/builds/15151
> https://build.chromium.org/p/chromium/builders/Linux%20x64/builds/19052
> 
> Original issue's description:
> > SkOncePtr -> SkOnce
> > 
> > It's always nice to kill off a synchronization primitive.
> > And while less terse, I think this new code reads more clearly.
> > 
> > ... and, SkOncePtr's tests were the only thing now using sk_num_cores()
> > outside of SkTaskGroup, so I've hidden it as static inside SkTaskGroup.cpp.
> > 
> > BUG=skia:
> > GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
> >
CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot
> > 
> > Committed:
https://skia.googlesource.com/skia/+/9bd3fc7fa9bb7cad050bd619aa93d4c48ebb5c02
> 
> TBR=herb@google.com,mtklein@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=skia:
> 
> Committed:
https://skia.googlesource.com/skia/+/7eb33da7eede34c050b865dbb1b60c3dcea7191b

TBR=herb@google.com,mtklein@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Committed:
https://skia.googlesource.com/skia/+/82da9a8aa0ce648f36882830765b42e0ada6c0fa
==========

[commit-bot: I haz the power, 2016-05-05 08:29:01]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/82da9a8aa0ce648f36882830765b42e0ada6c0fa

[reed1, 2016-05-05 08:36:32]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1948313002/ by reed@google.com.

The reason for reverting is: ok, I have no idea what's going on.