skia: Make the validate match interface for *_draw_instanced

skia: Make the validate match interface for *_draw_instanced

For whatever reason, on the Mac, the command buffer is reporting
ARB_draw_instanced as a valid extension. This is probably a bug in the
command buffer and I'll look into this later.

In Skia, we don't check for ARB_draw_instanced in GLES2 when building
the interface, but during the validate, we do, so we ended up failing
the validation.

Looking a bit further at the specs, ARB_draw_instanced is GL only,
whereas EXT_draw_instanced is both GL and GLES.  I've updated the code
to reflect this.

See:
https://cvs.khronos.org/svn/repos/ogl/trunk/doc/registry/public/specs/ARB/draw_instanced.txt
https://www.opengl.org/registry/specs/EXT/draw_instanced.txt

Everything above also applies to ARB/EXT_instanced_arrays

https://www.khronos.org/registry/gles/extensions/EXT/EXT_instanced_arrays.txt
https://www.opengl.org/registry/specs/ARB/instanced_arrays.txt

Committed: https://skia.googlesource.com/skia/+/b3f1636ec80e66188ddc01306672a9a79a954dfe

[hendrikw, 2015-10-16 23:34:23]

hendrikw@chromium.org changed reviewers:
+ bsalomon@google.com

[hendrikw, 2015-10-16 23:34:23]

PTAL, thanks!

[bsalomon, 2015-10-19 13:04:09]

On 2015/10/19 13:04:02, bsalomon wrote:

lgtm

[bsalomon, 2015-10-19 13:04:12]

The CQ bit was checked by bsalomon@google.com

[commit-bot: I haz the power, 2015-10-19 13:04:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1409053003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1409053003/1

[commit-bot: I haz the power, 2015-10-19 13:13:59]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/b3f1636ec80e66188ddc01306672a9a79a954dfe