move declaration of CreateLightingFilter into SkColorMatrixFilter

src/effects/SkColorFilters.cpp

Index: src/effects/SkColorFilters.cpp
diff --git a/src/effects/SkColorFilters.cpp b/src/effects/SkColorFilters.cpp
index 4515c0d3fefa52b398f4d312e30008184cb6b7f9..fe39dd980025c3ed4c7e39a5beb42d52b2e04646 100644
--- a/src/effects/SkColorFilters.cpp
+++ b/src/effects/SkColorFilters.cpp
@@ -14,7 +14,6 @@
 #include "SkUtils.h"
 #include "SkString.h"
 #include "SkValidationUtils.h"
-#include "SkColorMatrixFilter.h"
 
 bool SkModeColorFilter::asColorMode(SkColor* color, SkXfermode::Mode* mode) const {
     if (color) {
@@ -169,28 +168,3 @@ SkColorFilter* SkColorFilter::CreateModeFilter(SkColor color, SkXfermode::Mode m
             return SkModeColorFilter::Create(color, mode);
     }
 }
-
-///////////////////////////////////////////////////////////////////////////////
-
-static SkScalar byte_to_scale(U8CPU byte) {
-    if (0xFF == byte) {
-        // want to get this exact
-        return 1;
-    } else {
-        return byte * 0.00392156862745f;
-    }
-}
-
-SkColorFilter* SkColorFilter::CreateLightingFilter(SkColor mul, SkColor add) {
-    SkColorMatrix matrix;
-    matrix.setScale(byte_to_scale(SkColorGetR(mul)),
-                    byte_to_scale(SkColorGetG(mul)),
-                    byte_to_scale(SkColorGetB(mul)),
-                    1);
-    matrix.postTranslate(SkIntToScalar(SkColorGetR(add)),
-                         SkIntToScalar(SkColorGetG(add)),
-                         SkIntToScalar(SkColorGetB(add)),
-                         0);
-    return SkColorMatrixFilter::Create(matrix);
-}
-