Make GPU coord transforms automatic

include/gpu/GrTypes.h

Index: include/gpu/GrTypes.h
diff --git a/include/gpu/GrTypes.h b/include/gpu/GrTypes.h
index 2405679c0f8007b0c450d607d86d0aa9d39e4312..aba71aca33479ce6eeb944d48c9e548cca8ec3dd 100644
--- a/include/gpu/GrTypes.h
+++ b/include/gpu/GrTypes.h
@@ -241,6 +241,14 @@ enum GrBlendCoeff {
 };
 
 /**
+* Built-in coordinate sets provided by the framework.

[bsalomon, 2013/09/27 19:23:57]

Does anything get worse if this is moved to a less fundamental header, (e.g.
GrEffect.h or GrCoodTransform.h)? I've got no problem with it being non-nested
but I don't imagine this is useful for a user of Ganesh that isn't extending the
effect system and might just serve as a point of confusion.

Could use a little more explanation:

/**
 * Coordinates available to a GrEffect subclasses. Effects express matrices via
a GrCoordTransform that are applied to these coordinates. The transformed
coordinates are made available in the the portion of fragment shader emitted by
the effect.
 */
enum GrCoordSet {
/** The src-space coordinate that maps to the fragment being rendered. These
coords account for any change of coordinate system done on the CPU by GrContext
before rendering and also are correct for draws that take explicit local coords
rather than inferring them from the primitive's positions (e.g. drawVertices).
These are usually the coords desired by a GrEffect. */

kLocal_GrCoordSet,
/** The actual vertex position. Note that GrContext may not draw using the
original view matrix specified by when a caller draws as it may have transformed
vertices into another space. This is usually not the coordinates desired by a
GrEffect.*/
kPosition_GrCoordSet
};

Also, I kinda like GrCoordType or simply GrCoords over GrCoordSet... Don't
really love any of them.

+*/
+enum GrCoordSet {
+    kLocal_GrCoordSet,
+    kPosition_GrCoordSet
+};
+
+/**
  *  Formats for masks, used by the font cache.
  *  Important that these are 0-based.
  */