Add device space "nudge" to gpu draws

Add device space "nudge" to gpu draws

This CL nudges all the GPU draws and clips slightly to match raster's round behavior for BW draws. We assume the effect will be negligible and do it for AA draws too. 

BUG=423834
Committed: https://skia.googlesource.com/skia/+/2d55d07501c56310f97d2092d789a2bc9fa01b78

Committed: https://skia.googlesource.com/skia/+/b9329991426d0b77ea194a380d72d73fb855308a

[robertphillips, 2015-01-27 18:57:19]

robertphillips@google.com changed reviewers:
+ bsalomon@google.com

[bsalomon, 2015-01-27 20:23:59]

lgtm. Do you think we have adequate gm coverage (my gut is yes). I'd be curious
to know how much this decreases the number of unique images we produce across
all the bots. Not sure that we have a way to measure that.

[robertphillips, 2015-01-27 20:28:18]

I think GM coverage is all right. The new SampleApp slide is great b.c. it has
the animation but that wouldn't translate concisely to a GM.

I believe this will give us fewer overall images but I don't know any way to
measure that.

[robertphillips, 2015-01-28 12:46:14]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2015-01-28 12:46:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/877473005/70001

[robertphillips, 2015-01-28 12:47:47]

The CQ bit was unchecked by robertphillips@google.com

[robertphillips, 2015-01-28 22:40:57]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2015-01-28 22:41:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/877473005/70001

[commit-bot: I haz the power, 2015-01-28 22:42:00]

Committed patchset #5 (id:70001) as
https://skia.googlesource.com/skia/+/2d55d07501c56310f97d2092d789a2bc9fa01b78

[robertphillips, 2015-01-29 01:33:07]

A revert of this CL (patchset #5 id:70001) has been created in
https://codereview.chromium.org/888483003/ by robertphillips@google.com.

The reason for reverting is: Chrome pixel test :(.

[robertphillips, 2015-01-29 01:36:25]

A revert of this CL (patchset #5 id:70001) has been created in
https://codereview.chromium.org/890433003/ by robertphillips@google.com.

The reason for reverting is: Chrome pixel test :(.

[robertphillips, 2015-01-30 19:18:36]

The CQ bit was checked by robertphillips@google.com

[commit-bot: I haz the power, 2015-01-30 19:19:16]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/877473005/90001

[commit-bot: I haz the power, 2015-01-30 19:24:54]

Committed patchset #6 (id:90001) as
https://skia.googlesource.com/skia/+/b9329991426d0b77ea194a380d72d73fb855308a

[robertphillips, 2015-01-30 22:43:31]

A revert of this CL (patchset #6 id:90001) has been created in
https://codereview.chromium.org/886153002/ by robertphillips@google.com.

The reason for reverting is: Blink layout tests this time :(.