Add SkPaint::getHash().

Add SkPaint::getHash().

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/fb1fe4f51820731f557e765f8c71cba9a0d28048

[mtklein, 2014-10-07 15:22:00]

mtklein@google.com changed reviewers:
+ djsollen@google.com, mtklein@google.com, reed@google.com

[mtklein, 2014-10-07 15:22:04]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-10-07 15:23:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/637583002/1

[commit-bot: I haz the power, 2014-10-07 15:23:03]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2014-10-07 21:23 UTC

[commit-bot: I haz the power, 2014-10-07 15:23:07]

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

[commit-bot: I haz the power, 2014-10-07 15:23:08]

Presubmit check for 637583002-1 failed and returned exit status 1.

Running presubmit commit checks ...

** Presubmit ERRORS **
Since the CL is editing public API, you must have an LGTM from one of:
('reed@chromium.org', 'reed@google.com', 'bsalomon@chromium.org',
'bsalomon@google.com', 'djsollen@chromium.org', 'djsollen@google.com')

Presubmit checks took 1.5s to calculate.

Was the presubmit check useful? If not, run "git cl presubmit -v"
to figure out which PRESUBMIT.py was run, then run git blame
on the file to figure out who to ask for help.

[reed1, 2014-10-07 15:37:20]

lgtm

[reed1, 2014-10-07 15:37:34]

The CQ bit was checked by reed@google.com

[commit-bot: I haz the power, 2014-10-07 15:38:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/637583002/20001

[commit-bot: I haz the power, 2014-10-07 15:45:46]

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

[commit-bot: I haz the power, 2014-10-07 15:45:47]

Try jobs failed on following builders:
  Build-Ubuntu13.10-GCC4.8-Arm7-Debug-Android-Trybot on tryserver.skia
(http://108.170.220.76:10117/builders/Build-Ubuntu13.10-GCC4.8-Arm7-Debug-Andr...)

[mtklein, 2014-10-07 16:16:40]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-10-07 16:17:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/637583002/60001

[commit-bot: I haz the power, 2014-10-07 16:26:14]

Committed patchset #4 (id:60001) as fb1fe4f51820731f557e765f8c71cba9a0d28048