diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/core/SkAlphaRuns.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/core/SkAlphaRuns.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,73 @@
+
+/*
+ * Copyright 2006 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 "SkAntiRun.h"
+#include "SkUtils.h"
+
+void SkAlphaRuns::reset(int width) {
+    SkASSERT(width > 0);
+
+#ifdef SK_DEBUG
+    sk_memset16((uint16_t*)fRuns, (uint16_t)(-42), width);
+#endif
+    fRuns[0] = SkToS16(width);
+    fRuns[width] = 0;
+    fAlpha[0] = 0;
+
+    SkDEBUGCODE(fWidth = width;)
+    SkDEBUGCODE(this->validate();)
+}
+
+#ifdef SK_DEBUG
+    void SkAlphaRuns::assertValid(int y, int maxStep) const {
+        int max = (y + 1) * maxStep - (y == maxStep - 1);
+
+        const int16_t* runs = fRuns;
+        const uint8_t*   alpha = fAlpha;
+
+        while (*runs) {
+            SkASSERT(*alpha <= max);
+            alpha += *runs;
+            runs += *runs;
+        }
+    }
+
+    void SkAlphaRuns::dump() const {
+        const int16_t* runs = fRuns;
+        const uint8_t* alpha = fAlpha;
+
+        SkDebugf("Runs");
+        while (*runs) {
+            int n = *runs;
+
+            SkDebugf(" %02x", *alpha);
+            if (n > 1) {
+                SkDebugf(",%d", n);
+            }
+            alpha += n;
+            runs += n;
+        }
+        SkDebugf("\n");
+    }
+
+    void SkAlphaRuns::validate() const {
+        SkASSERT(fWidth > 0);
+
+        int         count = 0;
+        const int16_t*  runs = fRuns;
+
+        while (*runs) {
+            SkASSERT(*runs > 0);
+            count += *runs;
+            SkASSERT(count <= fWidth);
+            runs += *runs;
+        }
+        SkASSERT(count == fWidth);
+    }
+#endif