diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/core/SkMask.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/core/SkMask.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2007 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkMask.h"
+
+/** returns the product if it is positive and fits in 31 bits. Otherwise this
+    returns 0.
+ */
+static int32_t safeMul32(int32_t a, int32_t b) {
+    int64_t size = sk_64_mul(a, b);
+    if (size > 0 && sk_64_isS32(size)) {
+        return sk_64_asS32(size);
+    }
+    return 0;
+}
+
+size_t SkMask::computeImageSize() const {
+    return safeMul32(fBounds.height(), fRowBytes);
+}
+
+size_t SkMask::computeTotalImageSize() const {
+    size_t size = this->computeImageSize();
+    if (fFormat == SkMask::k3D_Format) {
+        size = safeMul32(SkToS32(size), 3);
+    }
+    return size;
+}
+
+/** We explicitly use this allocator for SkBimap pixels, so that we can
+    freely assign memory allocated by one class to the other.
+*/
+uint8_t* SkMask::AllocImage(size_t size) {
+    return (uint8_t*)sk_malloc_throw(SkAlign4(size));
+}
+
+/** We explicitly use this allocator for SkBimap pixels, so that we can
+    freely assign memory allocated by one class to the other.
+*/
+void SkMask::FreeImage(void* image) {
+    sk_free(image);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+static const int gMaskFormatToShift[] = {
+    ~0, // BW -- not supported
+    0,  // A8
+    0,  // 3D
+    2,  // ARGB32
+    1,  // LCD16
+    2   // LCD32
+};
+
+static int maskFormatToShift(SkMask::Format format) {
+    SkASSERT((unsigned)format < SK_ARRAY_COUNT(gMaskFormatToShift));
+    SkASSERT(SkMask::kBW_Format != format);
+    return gMaskFormatToShift[format];
+}
+
+void* SkMask::getAddr(int x, int y) const {
+    SkASSERT(kBW_Format != fFormat);
+    SkASSERT(fBounds.contains(x, y));
+    SkASSERT(fImage);
+
+    char* addr = (char*)fImage;
+    addr += (y - fBounds.fTop) * fRowBytes;
+    addr += (x - fBounds.fLeft) << maskFormatToShift(fFormat);
+    return addr;
+}