diff -r 000000000000 -r 6474c204b198 gfx/gl/GLReadTexImageHelper.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/gl/GLReadTexImageHelper.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim: set ts=8 sts=4 et sw=4 tw=80: */
+/* 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 GLREADTEXIMAGEHELPER_H_
+#define GLREADTEXIMAGEHELPER_H_
+
+#include "GLContextTypes.h"
+#include "mozilla/Attributes.h"
+#include "nsSize.h"
+#include "nsAutoPtr.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/gfx/Types.h"
+
+class gfxImageSurface;
+
+namespace mozilla {
+
+namespace gfx {
+class DataSourceSurface;
+}
+
+namespace gl {
+
+void ReadPixelsIntoImageSurface(GLContext* aGL, gfxImageSurface* aSurface);
+void ReadScreenIntoImageSurface(GLContext* aGL, gfxImageSurface* aSurface);
+
+TemporaryRef<gfx::DataSourceSurface>
+ReadBackSurface(GLContext* gl, GLuint aTexture, bool aYInvert, gfx::SurfaceFormat aFormat);
+
+class GLReadTexImageHelper MOZ_FINAL
+{
+    // The GLContext is the sole owner of the GLBlitHelper.
+    GLContext* mGL;
+
+    GLuint mPrograms[4];
+
+    GLuint TextureImageProgramFor(GLenum aTextureTarget, int aShader);
+
+    bool DidGLErrorOccur(const char* str);
+
+public:
+
+    GLReadTexImageHelper(GLContext* gl);
+    ~GLReadTexImageHelper();
+
+    /**
+      * Read the image data contained in aTexture, and return it as an ImageSurface.
+      * If GL_RGBA is given as the format, a gfxImageFormat::ARGB32 surface is returned.
+      * Not implemented yet:
+      * If GL_RGB is given as the format, a gfxImageFormat::RGB24 surface is returned.
+      * If GL_LUMINANCE is given as the format, a gfxImageFormat::A8 surface is returned.
+      *
+      * THIS IS EXPENSIVE.  It is ridiculously expensive.  Only do this
+      * if you absolutely positively must, and never in any performance
+      * critical path.
+      *
+      * NOTE: aShaderProgram is really mozilla::layers::ShaderProgramType. It is
+      * passed as int to eliminate including LayerManagerOGLProgram.h here.
+      */
+    TemporaryRef<gfx::DataSourceSurface> ReadTexImage(GLuint aTextureId,
+                                                      GLenum aTextureTarget,
+                                                      const gfx::IntSize& aSize,
+                              /* ShaderProgramType */ int aShaderProgram,
+                                                      bool aYInvert = false);
+
+
+};
+
+}
+}
+
+#endif