diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/core/SkMathPriv.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/core/SkMathPriv.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,71 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkMathPriv_DEFINED
+#define SkMathPriv_DEFINED
+
+#include "SkMath.h"
+
+/** Returns -1 if n < 0, else returns 0
+ */
+#define SkExtractSign(n)    ((int32_t)(n) >> 31)
+
+/** If sign == -1, returns -n, else sign must be 0, and returns n.
+ Typically used in conjunction with SkExtractSign().
+ */
+static inline int32_t SkApplySign(int32_t n, int32_t sign) {
+    SkASSERT(sign == 0 || sign == -1);
+    return (n ^ sign) - sign;
+}
+
+/** Return x with the sign of y */
+static inline int32_t SkCopySign32(int32_t x, int32_t y) {
+    return SkApplySign(x, SkExtractSign(x ^ y));
+}
+
+/** Given a positive value and a positive max, return the value
+ pinned against max.
+ Note: only works as long as max - value doesn't wrap around
+ @return max if value >= max, else value
+ */
+static inline unsigned SkClampUMax(unsigned value, unsigned max) {
+    if (value > max) {
+        value = max;
+    }
+    return value;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+/** Return a*b/255, truncating away any fractional bits. Only valid if both
+ a and b are 0..255
+ */
+static inline U8CPU SkMulDiv255Trunc(U8CPU a, U8CPU b) {
+    SkASSERT((uint8_t)a == a);
+    SkASSERT((uint8_t)b == b);
+    unsigned prod = SkMulS16(a, b) + 1;
+    return (prod + (prod >> 8)) >> 8;
+}
+
+/** Return (a*b)/255, taking the ceiling of any fractional bits. Only valid if
+ both a and b are 0..255. The expected result equals (a * b + 254) / 255.
+ */
+static inline U8CPU SkMulDiv255Ceiling(U8CPU a, U8CPU b) {
+    SkASSERT((uint8_t)a == a);
+    SkASSERT((uint8_t)b == b);
+    unsigned prod = SkMulS16(a, b) + 255;
+    return (prod + (prod >> 8)) >> 8;
+}
+
+/** Just the rounding step in SkDiv255Round: round(value / 255)
+ */
+static inline unsigned SkDiv255Round(unsigned prod) {
+    prod += 128;
+    return (prod + (prod >> 8)) >> 8;
+}
+
+#endif