Bug fix: we're using SkPMColor methods on SkColor

Bug fix: we're using SkPMColor methods on SkColor.

Annoyingly our test bot that forces SkPMFloat_none is a Linux bot using
BGRA SkPMColors, so we'd never notice the bug there.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/3679c1bbe7f1e611d7c06b1134e16049799a3ac6

[mtklein_C, 2015-08-19 18:03:10]

mtklein@chromium.org changed reviewers:
+ noel@chromium.org

[mtklein_C, 2015-08-19 18:03:20]

The CQ bit was checked by mtklein@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-08-19 18:03:27]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1296383006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1296383006/1

[commit-bot: I haz the power, 2015-08-19 18:10:15]

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

[commit-bot: I haz the power, 2015-08-19 18:10:15]

Dry run: This issue passed the CQ dry run.

[Noel Gordon, 2015-08-19 23:59:03]

LGTM.

[mtklein, 2015-08-20 00:05:12]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-08-20 00:05:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1296383006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1296383006/1

[commit-bot: I haz the power, 2015-08-20 00:05:37]

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 2015-08-20 06:05 UTC

[mtklein, 2015-08-20 00:05:43]

lgtm

[mtklein, 2015-08-20 00:05:46]

The CQ bit was unchecked by mtklein@google.com

[mtklein, 2015-08-20 00:05:50]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-08-20 00:06:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1296383006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1296383006/1

[commit-bot: I haz the power, 2015-08-20 00:06:41]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/3679c1bbe7f1e611d7c06b1134e16049799a3ac6

[mtklein, 2015-08-20 00:20:56]

On 2015/08/20 00:06:41, commit-bot: I haz the power wrote:
> Committed patchset #1 (id:1) as
> https://skia.googlesource.com/skia/+/3679c1bbe7f1e611d7c06b1134e16049799a3ac6

*SkPMColor methods