diff -r 000000000000 -r 6474c204b198 gfx/thebes/gfxReusableSharedImageSurfaceWrapper.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/thebes/gfxReusableSharedImageSurfaceWrapper.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,61 @@
+/* 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 GFXSHMCOWSURFACEWRAPPER
+#define GFXSHMCOWSURFACEWRAPPER
+
+#include "gfxReusableSurfaceWrapper.h"
+#include "mozilla/RefPtr.h"
+
+class gfxSharedImageSurface;
+
+namespace mozilla {
+namespace ipc {
+class Shmem;
+}
+namespace layers {
+class ISurfaceAllocator;
+}
+}
+
+/**
+ * A cross-process capable implementation of gfxReusableSurfaceWrapper based
+ * on gfxSharedImageSurface.
+ */
+class gfxReusableSharedImageSurfaceWrapper : public gfxReusableSurfaceWrapper {
+public:
+  gfxReusableSharedImageSurfaceWrapper(mozilla::layers::ISurfaceAllocator* aAllocator,
+                                       gfxSharedImageSurface* aSurface);
+  ~gfxReusableSharedImageSurfaceWrapper();
+
+  const unsigned char* GetReadOnlyData() const MOZ_OVERRIDE;
+  gfxImageFormat Format() MOZ_OVERRIDE;
+  gfxReusableSurfaceWrapper* GetWritable(gfxImageSurface** aSurface) MOZ_OVERRIDE;
+  void ReadLock() MOZ_OVERRIDE;
+  void ReadUnlock() MOZ_OVERRIDE;
+
+  Type GetType()
+  {
+    return TYPE_SHARED_IMAGE;
+  }
+
+  /**
+   * Returns the shared memory segment that backs the shared image surface.
+   */
+  mozilla::ipc::Shmem& GetShmem();
+
+  /**
+   * Create a gfxReusableSurfaceWrapper from the shared memory segment of a
+   * gfxSharedImageSurface. A ReadLock must be held, which will be adopted by
+   * the returned gfxReusableSurfaceWrapper.
+   */
+  static already_AddRefed<gfxReusableSharedImageSurfaceWrapper>
+  Open(mozilla::layers::ISurfaceAllocator* aAllocator, const mozilla::ipc::Shmem& aShmem);
+
+private:
+  mozilla::RefPtr<mozilla::layers::ISurfaceAllocator> mAllocator;
+  nsRefPtr<gfxSharedImageSurface>         mSurface;
+};
+
+#endif // GFXSHMCOWSURFACEWRAPPER