Start canonicalizing color for all A8 textblobs

include/core/SkPaint.h

Index: include/core/SkPaint.h
diff --git a/include/core/SkPaint.h b/include/core/SkPaint.h
index 991a727f935498cbf9d716313e1089d034026221..138dc4f86d4245ad85d30aecbccdb039b76597d9 100644
--- a/include/core/SkPaint.h
+++ b/include/core/SkPaint.h
@@ -1076,6 +1076,8 @@ private:
                         void (*proc)(SkTypeface*, const SkDescriptor*, void*),
                         void* context, bool ignoreGamma = false) const;
 
+    SkColor computeLuminanceColor() const;

[bsalomon, 2015/04/13 15:16:38]

comment about what luminance color is? Or is this something that already has a
clear meaning in Skia?

+
     static void Term();
 
     enum {
@@ -1129,6 +1131,7 @@ private:
     friend class GrPathRendering;
     friend class GrTextContext;
     friend class GrGLPathRendering;
+    friend class SkScalerContext;
     friend class SkTextToPathIter;
     friend class SkCanonicalizePaint;
 };