Spin off just SkLazyFnPtr from 305513002.

Spin off just SkLazyFnPtr from 305513002.

The memory barrier in SkOnce is a perf regression for sk_mem{set,cpy} in
SkUtils on ARM.  We can do a lot better for function pointers.

BUG=skia:

Committed: http://code.google.com/p/skia/source/detail?r=14929

Committed: http://code.google.com/p/skia/source/detail?r=14938

[bungeman-skia, 2014-05-28 19:04:27]

lgtm, so long as SkThread.h and SkThreadPriv.h all get back together soon.

[mtklein, 2014-05-28 19:10:20]

On 2014/05/28 19:04:27, bungeman1 wrote:
> lgtm, so long as SkThread.h and SkThreadPriv.h all get back together soon.

Done!

[mtklein, 2014-05-28 19:27:10]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-05-28 19:27:26]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/mtklein@chromium.org/305753002/70001

[commit-bot: I haz the power, 2014-05-28 19:40:33]

Change committed as 14929

[mtklein, 2014-05-28 19:57:48]

A revert of this CL has been created in
https://codereview.chromium.org/300843012/ by mtklein@google.com.

The reason for reverting is: depends on bad cl.

[mtklein, 2014-05-28 20:14:09]

On 2014/05/28 19:57:48, mtklein wrote:
> A revert of this CL has been created in
> https://codereview.chromium.org/300843012/ by mailto:mtklein@google.com.
> 
> The reason for reverting is: depends on bad cl.

Will retry this one tomorrow using the SkThreadPriv strategy.

[mtklein, 2014-05-28 21:03:07]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-05-28 21:03:19]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/mtklein@chromium.org/305753002/90001

[commit-bot: I haz the power, 2014-05-28 21:44:02]

Change committed as 14938