Add a GrCustomCoordsTextureEffect class

Add a GrCustomCoordsTextureEffect class

Extracts a GrCustomCoordsTextureEffect class from
GrSimpleTextureEffect. This way there are no effects that can
conditionally require a vertex shader. They either always need one or
never do. Also removes kCustom_CoordsType from the CoordsType enum in
GrEffect (that enum is really only meant for coords provided by the
framework), and updates GrSimpleTextureEffect::TestCreate to make the
effect with position as well, instead of just local coords.

Committed: http://code.google.com/p/skia/source/detail?r=11531

[bsalomon, 2013-09-23 14:13:48]

lgtm w/ some minor nit comments.

https://codereview.chromium.org/24018007/diff/1/src/gpu/effects/GrCustomCoord...
File src/gpu/effects/GrCustomCoordsTextureEffect.cpp (right):

https://codereview.chromium.org/24018007/diff/1/src/gpu/effects/GrCustomCoord...
src/gpu/effects/GrCustomCoordsTextureEffect.cpp:2: * Copyright 2012 Google Inc.
2013

https://codereview.chromium.org/24018007/diff/1/src/gpu/effects/GrCustomCoord...
src/gpu/effects/GrCustomCoordsTextureEffect.cpp:94: GrContext*,
can you align the wrapped params with "SkRandom random,"?

[commit-bot: I haz the power, 2013-09-30 18:15:55]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/cdalton@nvidia.com/24018007/6001

[commit-bot: I haz the power, 2013-09-30 18:41:45]

Change committed as 11531