first cut at HQ GPU scaling; refactored existing bicubic scaler

include/effects/SkBicubicImageFilter.h

Index: include/effects/SkBicubicImageFilter.h
diff --git a/include/effects/SkBicubicImageFilter.h b/include/effects/SkBicubicImageFilter.h
index bd918eb769d7740988680a67638063e0e81b5183..7e18705c648500c1d56ade184c31e901c9e4e36a 100644
--- a/include/effects/SkBicubicImageFilter.h
+++ b/include/effects/SkBicubicImageFilter.h
@@ -34,6 +34,8 @@ public:
 
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkBicubicImageFilter)
 
+    static const SkScalar fMitchellCoefficients[16];

[bsalomon, 2013/09/03 20:55:17]

style-nit: statics aren't fSomething. Maybe gMitchellCoeffecients or
kMitchellCoeffecients.

(There is some ambiguity in the existing code about whether the 'k' prefix
stands for a Kompile-time of any type or more narrowly just a Kinteger.

+
 protected:
     SkBicubicImageFilter(SkFlattenableReadBuffer& buffer);
     virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;