diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/include/effects/SkArithmeticMode.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/include/effects/SkArithmeticMode.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkArithmeticMode_DEFINED
+#define SkArithmeticMode_DEFINED
+
+#include "SkFlattenable.h"
+#include "SkScalar.h"
+
+class SkXfermode;
+
+class SK_API SkArithmeticMode {
+public:
+    /**
+     *  result = clamp[k1 * src * dst + k2 * src + k3 * dst + k4]
+     *
+     *  src and dst are treated as being [0.0 .. 1.0]. The polynomial is
+     *  evaluated on their unpremultiplied components.
+     *
+     *  k1=k2=k3=0, k4=1.0 results in returning opaque white
+     *  k1=k3=k4=0, k2=1.0 results in returning the src
+     *  k1=k2=k4=0, k3=1.0 results in returning the dst
+     */
+    static SkXfermode* Create(SkScalar k1, SkScalar k2,
+                              SkScalar k3, SkScalar k4);
+
+    SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP();
+
+private:
+    SkArithmeticMode(); // can't be instantiated
+};
+
+#endif