diff -r 000000000000 -r 6474c204b198 gfx/2d/SourceSurfaceDual.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/2d/SourceSurfaceDual.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+  * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+     
+#ifndef MOZILLA_GFX_SOURCESURFACEDUAL_H_
+#define MOZILLA_GFX_SOURCESURFACEDUAL_H_
+     
+#include "2D.h"
+     
+namespace mozilla {
+namespace gfx {
+
+class DualSurface;
+class DualPattern;
+
+class SourceSurfaceDual : public SourceSurface
+{
+public:
+  MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(SourceSurfaceDual)
+  SourceSurfaceDual(DrawTarget *aDTA, DrawTarget *aDTB)
+    : mA(aDTA->Snapshot())
+    , mB(aDTB->Snapshot())
+  { }
+
+  virtual SurfaceType GetType() const { return SurfaceType::DUAL_DT; }
+  virtual IntSize GetSize() const { return mA->GetSize(); }
+  virtual SurfaceFormat GetFormat() const { return mA->GetFormat(); }
+
+  /* Readback from this surface type is not supported! */
+  virtual TemporaryRef<DataSourceSurface> GetDataSurface() { return nullptr; }
+private:
+  friend class DualSurface;
+  friend class DualPattern;
+
+  RefPtr<SourceSurface> mA;
+  RefPtr<SourceSurface> mB;
+};
+
+}
+}
+
+#endif /* MOZILLA_GFX_SOURCESURFACEDUAL_H_ */