Tessellator: better fix for reused-edges issue.

Tessellator: better fix for reused-edges issue.

The GrTessellator fix for doubly-added edges in
https://codereview.chromium.org/2259493002/ could leave
a MonotonePoly with zero edges. This is a problem for
Poly::addEdge(), which assumes that MonotonePolys always have
at least one edge. The fix is to move the check and early-out up to
Poly::addEdge(). This should also tighten up the vertex count.

(Unfortunately, the only repro I have for this issue is very
convoluted, and requires non-landed code.)

BUG=skia:5636
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251643008

Committed: https://skia.googlesource.com/skia/+/212c7c389e81053b84a3ed7775f2031d76d5ee70

[Stephen White, 2016-08-18 15:36:37]

Description was changed from

==========
Tessellator: better fix for reused-edges issue.

The GrTessellator fix for doubly-added edges in
https://codereview.chromium.org/2259493002/ could leave
a MonotonePoly with zero edges. This is a problem for
Poly::addEdge(), which assumes that MonotonePolys always have
at least one edge. The fix is to move the check and early-out up to
Poly::addEdge(). This should also tighten up the vertex count.

(Unfortunately, the only repro I have for this issue is very
convoluted, and requires non-landed code.)

BUG=skia:5636
==========

to

==========
Tessellator: better fix for reused-edges issue.

The GrTessellator fix for doubly-added edges in
https://codereview.chromium.org/2259493002/ could leave
a MonotonePoly with zero edges. This is a problem for
Poly::addEdge(), which assumes that MonotonePolys always have
at least one edge. The fix is to move the check and early-out up to
Poly::addEdge(). This should also tighten up the vertex count.

(Unfortunately, the only repro I have for this issue is very
convoluted, and requires non-landed code.)

BUG=skia:5636
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251643008
==========

[Stephen White, 2016-08-18 15:37:10]

Description was changed from

==========
Tessellator: better fix for reused-edges issue.

The GrTessellator fix for doubly-added edges in
https://codereview.chromium.org/2259493002/ could leave
a MonotonePoly with zero edges. This is a problem for
Poly::addEdge(), which assumes that MonotonePolys always have
at least one edge. The fix is to move the check and early-out up to
Poly::addEdge(). This should also tighten up the vertex count.

(Unfortunately, the only repro I have for this issue is very
convoluted, and requires non-landed code.)

BUG=skia:5636
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251643008
==========

to

==========
Tessellator: better fix for reused-edges issue.

The GrTessellator fix for doubly-added edges in
https://codereview.chromium.org/2259493002/ could leave
a MonotonePoly with zero edges. This is a problem for
Poly::addEdge(), which assumes that MonotonePolys always have
at least one edge. The fix is to move the check and early-out up to
Poly::addEdge(). This should also tighten up the vertex count.

(Unfortunately, the only repro I have for this issue is very
convoluted, and requires non-landed code.)

BUG=skia:5636
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251643008
==========

[Stephen White, 2016-08-18 15:37:10]

senorblanco@chromium.org changed reviewers:
+ robertphillips@google.com

[Stephen White, 2016-08-18 15:37:16]

The CQ bit was checked by senorblanco@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-08-18 15:37:23]

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

[Stephen White, 2016-08-18 15:37:24]

robertphillips@: PTAL. Thanks!

[commit-bot: I haz the power, 2016-08-18 16:00:13]

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

[commit-bot: I haz the power, 2016-08-18 16:00:15]

Dry run: This issue passed the CQ dry run.

[robertphillips, 2016-08-18 17:18:57]

lgtm

[Stephen White, 2016-08-18 17:19:26]

The CQ bit was checked by senorblanco@chromium.org

[commit-bot: I haz the power, 2016-08-18 17:19:33]

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, 2016-08-18 17:20:52]

Description was changed from

==========
Tessellator: better fix for reused-edges issue.

The GrTessellator fix for doubly-added edges in
https://codereview.chromium.org/2259493002/ could leave
a MonotonePoly with zero edges. This is a problem for
Poly::addEdge(), which assumes that MonotonePolys always have
at least one edge. The fix is to move the check and early-out up to
Poly::addEdge(). This should also tighten up the vertex count.

(Unfortunately, the only repro I have for this issue is very
convoluted, and requires non-landed code.)

BUG=skia:5636
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251643008
==========

to

==========
Tessellator: better fix for reused-edges issue.

The GrTessellator fix for doubly-added edges in
https://codereview.chromium.org/2259493002/ could leave
a MonotonePoly with zero edges. This is a problem for
Poly::addEdge(), which assumes that MonotonePolys always have
at least one edge. The fix is to move the check and early-out up to
Poly::addEdge(). This should also tighten up the vertex count.

(Unfortunately, the only repro I have for this issue is very
convoluted, and requires non-landed code.)

BUG=skia:5636
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2251643008

Committed:
https://skia.googlesource.com/skia/+/212c7c389e81053b84a3ed7775f2031d76d5ee70
==========

[commit-bot: I haz the power, 2016-08-18 17:20:53]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/212c7c389e81053b84a3ed7775f2031d76d5ee70