Gamma correction for distance field text.

src/core/SkScalerContext.h

Index: src/core/SkScalerContext.h
diff --git a/src/core/SkScalerContext.h b/src/core/SkScalerContext.h
index f18d217f6208e6628bd02c2e71a69331e65fc30d..af83685eb69dc96c782dc5eb13ecf133ad000cfd 100644
--- a/src/core/SkScalerContext.h
+++ b/src/core/SkScalerContext.h
@@ -184,6 +184,17 @@ public:
     void        getPath(const SkGlyph&, SkPath*);
     void        getFontMetrics(SkPaint::FontMetrics*);
 
+    /** Return the size in bytes of the associated gamma lookup table
+     */
+    static size_t GetGammaLUTSize(SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma,
+                                  int* width, int* height);
+
+    /** Get the associated gamma lookup table. The 'data' pointer must point to pre-allocated
+        memory, with size in bytes greater than or equal to the return value of getGammaLUTSize().
+     */
+    static void   GetGammaLUTData(SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma,
+                                  void* data);
+
 #ifdef SK_BUILD_FOR_ANDROID
     unsigned getBaseGlyphCount(SkUnichar charCode);