diff -r 000000000000 -r 6474c204b198 gfx/layers/basic/BasicCanvasLayer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/layers/basic/BasicCanvasLayer.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,51 @@
+/* -*- Mode: C++; tab-width: 2; 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 GFX_BASICCANVASLAYER_H
+#define GFX_BASICCANVASLAYER_H
+
+#include "BasicImplData.h"              // for BasicImplData
+#include "BasicLayers.h"                // for BasicLayerManager
+#include "CopyableCanvasLayer.h"        // for CopyableCanvasLayer
+#include "Layers.h"                     // for CanvasLayer, etc
+#include "nsDebug.h"                    // for NS_ASSERTION
+#include "nsRegion.h"                   // for nsIntRegion
+
+class gfxContext;
+
+namespace mozilla {
+namespace layers {
+
+class BasicCanvasLayer : public CopyableCanvasLayer,
+                         public BasicImplData
+{
+public:
+  BasicCanvasLayer(BasicLayerManager* aLayerManager) :
+    CopyableCanvasLayer(aLayerManager,
+                        static_cast<BasicImplData*>(MOZ_THIS_IN_INITIALIZER_LIST()))
+  { }
+  
+  virtual void SetVisibleRegion(const nsIntRegion& aRegion)
+  {
+    NS_ASSERTION(BasicManager()->InConstruction(),
+                 "Can only set properties in construction phase");
+    CanvasLayer::SetVisibleRegion(aRegion);
+  }
+  
+  virtual void Paint(gfx::DrawTarget* aDT,
+                     const gfx::Point& aDeviceOffset,
+                     Layer* aMaskLayer) MOZ_OVERRIDE;
+ 
+protected:
+  BasicLayerManager* BasicManager()
+  {
+    return static_cast<BasicLayerManager*>(mManager);
+  }
+};
+
+}
+}
+
+#endif