Perform SkPicture analysis lazily.

Perform SkPicture analysis lazily.

I realized when writing the comment on https://crrev.com/1135363002/
that I'd really just sketched out the entire thing, so I couldn't help
but actually write up a working CL.  How does this do for your benchmark?

BUG=chromium:487075
Committed: https://skia.googlesource.com/skia/+/c30806f9f16e6400036fdc25842b73a9d2a41cb3

[mtklein, 2015-05-13 13:46:21]

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

[commit-bot: I haz the power, 2015-05-13 13:46:28]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1130123006/1

[mtklein_C, 2015-05-13 13:51:45]

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

[mtklein_C, 2015-05-13 13:53:22]

mtklein@chromium.org changed reviewers:
+ junchao.han@intel.com

[commit-bot: I haz the power, 2015-05-13 13:55:19]

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

[commit-bot: I haz the power, 2015-05-13 13:55:20]

Dry run: This issue passed the CQ dry run.

[reed1, 2015-05-13 15:06:50]

reed@google.com changed reviewers:
+ reed@google.com

[reed1, 2015-05-13 15:06:51]

api lgtm

[junchao.han, 2015-05-14 01:41:11]

The patch looks great and BrowserMark 2.1 SVG case will enjoy ~10% performance
improvement on Galaxy S5. Let's merge your patch.

[mtklein, 2015-05-14 02:25:54]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-05-14 02:26:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1130123006/1

[commit-bot: I haz the power, 2015-05-14 02:26:22]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/c30806f9f16e6400036fdc25842b73a9d2a41cb3