move declaration of CreateLightingFilter into SkColorMatrixFilter

src/effects/SkColorMatrixFilter.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorMatrixFilter.h"
 #include "SkColorMatrix.h"
 #include "SkColorPriv.h"
@@ skipping 320 matching lines @@
     str->append("matrix: (");
     for (int i = 0; i < 20; ++i) {
         str->appendScalar(fMatrix.fMat[i]);
         if (i < 19) {
             str->append(", ");
         }
     }
     str->append(")");
 }
 #endif
+
+///////////////////////////////////////////////////////////////////////////////
+
+static SkScalar byte_to_scale(U8CPU byte) {
+    if (0xFF == byte) {
+        // want to get this exact
+        return 1;
+    } else {
+        return byte * 0.00392156862745f;
+    }
+}
+
+SkColorFilter* SkColorMatrixFilter::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);
+}
+
+// DEPRECTED -- remove this when chrome/android stop calling it
+SkColorFilter* SkColorFilter::CreateLightingFilter(SkColor mul, SkColor add) {
+    return SkColorMatrixFilter::CreateLightingFilter(mul, add);
+}