Replace SkProxyCanvas with SkNWayCanvas.

Replace SkProxyCanvas with SkNWayCanvas.

We are removing SkProxyCanvas, which is a subset of SkNWayCanvas.

BUG=skia:3279
Committed: https://crrev.com/f3b7c52abef600ea38edfc12ab167f4e33c33811
Cr-Commit-Position: refs/heads/master@{#313751}

[scroggo, 2015-01-29 14:39:30]

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

[reed1, 2015-01-29 15:54:36]

lgtm

[scroggo, 2015-01-29 16:47:15]

scroggo@google.com changed reviewers:
+ fmalita@gmail.com

[scroggo, 2015-01-29 16:47:15]

Florin, will you please review? I think I need some more types of approval
before I can submit...

[f(malita), 2015-01-29 17:38:34]

fmalita@chromium.org changed reviewers:
+ fmalita@chromium.org

[f(malita), 2015-01-29 17:38:34]

The CQ bit was checked by fmalita@chromium.org

[f(malita), 2015-01-29 17:38:34]

lgtm

[commit-bot: I haz the power, 2015-01-29 17:39:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/876933005/1

[commit-bot: I haz the power, 2015-01-29 17:46:54]

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

[commit-bot: I haz the power, 2015-01-29 17:46:55]

Try jobs failed on following builders:
  linux_chromium_gn_dbg on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[scroggo, 2015-01-29 18:13:05]

The CQ bit was checked by scroggo@google.com

[commit-bot: I haz the power, 2015-01-29 18:14:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/876933005/20001

[commit-bot: I haz the power, 2015-01-29 19:10:46]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-01-29 19:12:06]

Patchset 2 (id:??) landed as
https://crrev.com/f3b7c52abef600ea38edfc12ab167f4e33c33811
Cr-Commit-Position: refs/heads/master@{#313751}