Add disableStencil method to GrGLGpu

Add disableStencil method to GrGLGpu

Most the calls to flushStencil were just trying to disable it. This
change cleans up that code so it can just call "disableStencil"
instead of having to muck with GrStencilSettings. It should also make
those calls slightly faster.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2453793002

Committed: https://skia.googlesource.com/skia/+/c7d853343a42e28edd9c38a3308afaa846fce1bc

[csmartdalton, 2016-10-26 16:10:46]

Description was changed from

==========
Add disableStencil method to GrGLGpu

Most the calls to flushStencil were just trying to disable it. This
change cleans up that code so it can just call "disableStencil"
instead of having to muck with GrStencilSettings. It should also make
those calls slightly faster.

BUG=skia:
==========

to

==========
Add disableStencil method to GrGLGpu

Most the calls to flushStencil were just trying to disable it. This
change cleans up that code so it can just call "disableStencil"
instead of having to muck with GrStencilSettings. It should also make
those calls slightly faster.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2453793002
==========

[csmartdalton, 2016-10-26 16:33:39]

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

[bsalomon, 2016-10-26 16:37:09]

lgtm

[csmartdalton, 2016-10-26 16:53:08]

The CQ bit was checked by csmartdalton@google.com

[commit-bot: I haz the power, 2016-10-26 16:53:13]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-26 17:13:48]

Description was changed from

==========
Add disableStencil method to GrGLGpu

Most the calls to flushStencil were just trying to disable it. This
change cleans up that code so it can just call "disableStencil"
instead of having to muck with GrStencilSettings. It should also make
those calls slightly faster.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2453793002
==========

to

==========
Add disableStencil method to GrGLGpu

Most the calls to flushStencil were just trying to disable it. This
change cleans up that code so it can just call "disableStencil"
instead of having to muck with GrStencilSettings. It should also make
those calls slightly faster.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2453793002

Committed:
https://skia.googlesource.com/skia/+/c7d853343a42e28edd9c38a3308afaa846fce1bc
==========

[commit-bot: I haz the power, 2016-10-26 17:13:49]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/c7d853343a42e28edd9c38a3308afaa846fce1bc