Port SkLazyFnPtr users to SkOncePtr.

Port SkLazyFnPtr users to SkOncePtr.

First baby step on road to replacing SkLazyFnPtr, SkLazyPtr, and SkOnce.

One of those very unusual times you get to use a function type, 
not a function pointer type!

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/bbd40183ae5f5dd3ae6e8ad3cf89cf5c27ce754b

[mtklein, 2015-09-08 13:27:38]

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

[commit-bot: I haz the power, 2015-09-08 13:27:42]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317263007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317263007/1

[mtklein_C, 2015-09-08 13:28:44]

mtklein@chromium.org changed reviewers:
+ herb@google.com
- mtklein@google.com

[mtklein_C, 2015-09-08 13:28:44]

This is an easy one.

[commit-bot: I haz the power, 2015-09-08 13:37:05]

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

[commit-bot: I haz the power, 2015-09-08 13:37:06]

Dry run: This issue passed the CQ dry run.

[herb_g, 2015-09-08 14:29:23]

lgtm

[mtklein, 2015-09-08 15:18:56]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-09-08 15:19:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1317263007/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1317263007/1

[commit-bot: I haz the power, 2015-09-08 15:19:37]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/bbd40183ae5f5dd3ae6e8ad3cf89cf5c27ce754b