Revert "Revert "add new signature so skia can rely on it (subclass of SkDevice)""

Revert "Revert "add new signature so skia can rely on it (subclass of SkDevice)""

Now with "override" to merge with skia's new virtual

Intended to allow this to land in skia
https://codereview.chromium.org/1005183003

This reverts commit 3d4669df835748357f3865d6d01a155fe72f298e.

BUG=
TBR=fmalita@chromium.org

Committed: https://crrev.com/3d74de25969674b68feb6080d947b3414c3963cd
Cr-Commit-Position: refs/heads/master@{#320659}

[reed2, 2015-03-14 13:36:15]

The CQ bit was checked by reed@chromium.org

[commit-bot: I haz the power, 2015-03-14 13:36:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1009053002/1

[reed2, 2015-03-14 13:50:19]

The CQ bit was checked by reed@chromium.org

[commit-bot: I haz the power, 2015-03-14 13:50:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1009053002/20001

[reed2, 2015-03-14 14:27:49]

The CQ bit was unchecked by reed@chromium.org

[reed2, 2015-03-14 16:33:50]

The CQ bit was checked by reed@chromium.org

[commit-bot: I haz the power, 2015-03-14 16:33:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1009053002/20001

[commit-bot: I haz the power, 2015-03-14 17:11:48]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-03-14 17:12:41]

Patchset 2 (id:??) landed as
https://crrev.com/3d74de25969674b68feb6080d947b3414c3963cd
Cr-Commit-Position: refs/heads/master@{#320659}