diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/utils/SkCanvasStack.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/utils/SkCanvasStack.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,53 @@
+
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkCanvasStack_DEFINED
+#define SkCanvasStack_DEFINED
+
+#include "SkNWayCanvas.h"
+#include "SkTArray.h"
+
+class SkCanvasStack : public SkNWayCanvas {
+public:
+    SkCanvasStack(int width, int height);
+    virtual ~SkCanvasStack();
+
+    void pushCanvas(SkCanvas* canvas, const SkIPoint& origin);
+    virtual void removeAll() SK_OVERRIDE;
+
+    /*
+     * The following add/remove canvas methods are overrides from SkNWayCanvas
+     * that do not make sense in the context of our CanvasStack, but since we
+     * can share most of the other implementation of NWay we override those
+     * methods to be no-ops.
+     */
+    virtual void addCanvas(SkCanvas*) SK_OVERRIDE { SkDEBUGFAIL("Invalid Op"); }
+    virtual void removeCanvas(SkCanvas*) SK_OVERRIDE { SkDEBUGFAIL("Invalid Op"); }
+
+protected:
+    virtual void didSetMatrix(const SkMatrix&) SK_OVERRIDE;
+
+    virtual void onClipRect(const SkRect&, SkRegion::Op, ClipEdgeStyle) SK_OVERRIDE;
+    virtual void onClipRRect(const SkRRect&, SkRegion::Op, ClipEdgeStyle) SK_OVERRIDE;
+    virtual void onClipPath(const SkPath&, SkRegion::Op, ClipEdgeStyle) SK_OVERRIDE;
+    virtual void onClipRegion(const SkRegion&, SkRegion::Op) SK_OVERRIDE;
+
+private:
+    void clipToZOrderedBounds();
+
+    struct CanvasData {
+        SkIPoint origin;
+        SkRegion requiredClip;
+    };
+
+    SkTArray<CanvasData> fCanvasData;
+
+    typedef SkNWayCanvas INHERITED;
+};
+
+#endif