Break GrTextContext's reliance on SkGpuDevice

Break GrTextContext's reliance on SkGpuDevice

This CL seems to have 2 main downsides:

1) It duplicates some code in SkBaseDevice::filterTextFlags
2) It makes it tougher to derive from SkGpuDevice

It seems reasonable (at least to me) that the TextContexts get the power to reset the LCD flags.

Committed: https://skia.googlesource.com/skia/+/9c240a1e6d314056fe0d6a8a33a3c60a6e19288f

[robertphillips, 2015-05-27 19:40:04]

robertphillips@google.com changed reviewers:
+ bsalomon@google.com, joshualitt@chromium.org, joshualitt@google.com

[bsalomon, 2015-05-27 20:39:16]

lgtm. Re pt 2, I'd be happy to mark SkGpuDevice final.

Can the SkGpuDevice stuff in GrContext.h be removed too?

[robertphillips, 2015-05-28 11:56:48]

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

[commit-bot: I haz the power, 2015-05-28 11:57:00]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1159973002/20001

[commit-bot: I haz the power, 2015-05-28 12:02:19]

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

[commit-bot: I haz the power, 2015-05-28 12:02:20]

Dry run: This issue passed the CQ dry run.

[robertphillips, 2015-05-28 14:45:15]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2015-05-28 14:45:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1159973002/20001

[commit-bot: I haz the power, 2015-05-28 14:46:04]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/9c240a1e6d314056fe0d6a8a33a3c60a6e19288f

[robertphillips, 2015-05-28 14:47:07]

The SkGpuDevice stuff in GrContext.h can't be removed until the TextContext is
behind the GrContext (so the SkGpuDevice won't be creating it).