diff -r 000000000000 -r 6474c204b198 gfx/layers/CopyableCanvasLayer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/layers/CopyableCanvasLayer.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,76 @@
+/* -*- 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_COPYABLECANVASLAYER_H
+#define GFX_COPYABLECANVASLAYER_H
+
+#include <stdint.h>                     // for uint32_t
+#include "GLContextTypes.h"             // for GLContext
+#include "Layers.h"                     // for CanvasLayer, etc
+#include "gfxContext.h"                 // for gfxContext, etc
+#include "gfxTypes.h"
+#include "gfxPlatform.h"                // for gfxImageFormat
+#include "mozilla/Assertions.h"         // for MOZ_ASSERT, etc
+#include "mozilla/Preferences.h"        // for Preferences
+#include "mozilla/RefPtr.h"             // for RefPtr
+#include "mozilla/gfx/2D.h"             // for DrawTarget
+#include "mozilla/mozalloc.h"           // for operator delete, etc
+#include "nsAutoPtr.h"                  // for nsRefPtr
+#include "nsISupportsImpl.h"            // for MOZ_COUNT_CTOR, etc
+
+namespace mozilla {
+
+namespace gfx {
+class SurfaceStream;
+class SharedSurface;
+class SurfaceFactory;
+}
+
+namespace layers {
+
+class CanvasClientWebGL;
+
+/**
+ * A shared CanvasLayer implementation that supports copying
+ * its contents into a gfxASurface using UpdateSurface.
+ */
+class CopyableCanvasLayer : public CanvasLayer
+{
+public:
+  CopyableCanvasLayer(LayerManager* aLayerManager, void *aImplData);
+  virtual ~CopyableCanvasLayer();
+
+  virtual void Initialize(const Data& aData);
+
+  virtual bool IsDataValid(const Data& aData);
+
+protected:
+  void UpdateTarget(gfx::DrawTarget* aDestTarget = nullptr);
+
+  RefPtr<gfx::SourceSurface> mSurface;
+  nsRefPtr<mozilla::gl::GLContext> mGLContext;
+  mozilla::RefPtr<mozilla::gfx::DrawTarget> mDrawTarget;
+
+  RefPtr<gfx::SurfaceStream> mStream;
+
+  uint32_t mCanvasFramebuffer;
+
+  bool mIsGLAlphaPremult;
+  bool mNeedsYFlip;
+
+  RefPtr<gfx::DataSourceSurface> mCachedTempSurface;
+  gfx::IntSize mCachedSize;
+  gfx::SurfaceFormat mCachedFormat;
+
+  gfx::DataSourceSurface* GetTempSurface(const gfx::IntSize& aSize,
+                                         const gfx::SurfaceFormat aFormat);
+
+  void DiscardTempSurface();
+};
+
+}
+}
+
+#endif