diff -r 000000000000 -r 6474c204b198 gfx/2d/DataSurfaceHelpers.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/2d/DataSurfaceHelpers.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,67 @@
+/* -*- 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_DATASURFACEHELPERS_H
+#define _MOZILLA_GFX_DATASURFACEHELPERS_H
+
+#include "2D.h"
+
+namespace mozilla {
+namespace gfx {
+
+void
+ConvertBGRXToBGRA(uint8_t* aData, const IntSize &aSize, int32_t aStride);
+
+/**
+ * Copy the pixel data from aSrc and pack it into aDst. aSrcSize, aSrcStride
+ * and aBytesPerPixel give the size, stride and bytes per pixel for aSrc's
+ * surface. Callers are responsible for making sure that aDst is big enough to
+ * contain |aSrcSize.width * aSrcSize.height * aBytesPerPixel| bytes.
+ */
+void
+CopySurfaceDataToPackedArray(uint8_t* aSrc, uint8_t* aDst, IntSize aSrcSize,
+                             int32_t aSrcStride, int32_t aBytesPerPixel);
+
+/**
+ * Convert aSurface to a packed buffer in BGRA format. The pixel data is
+ * returned in a buffer allocated with new uint8_t[]. The caller then has
+ * ownership of the buffer and is responsible for delete[]'ing it.
+ */
+uint8_t*
+SurfaceToPackedBGRA(DataSourceSurface *aSurface);
+
+/**
+ * Convert aSurface to a packed buffer in BGR format. The pixel data is
+ * returned in a buffer allocated with new uint8_t[]. The caller then has
+ * ownership of the buffer and is responsible for delete[]'ing it.
+ *
+ * This function is currently only intended for use with surfaces of format
+ * SurfaceFormat::B8G8R8X8 since the X components of the pixel data (if any)
+ * are simply dropped (no attempt is made to un-pre-multiply alpha from the
+ * color components).
+ */
+uint8_t*
+SurfaceToPackedBGR(DataSourceSurface *aSurface);
+
+/**
+ * Multiplies aStride and aHeight and makes sure the result is limited to
+ * something sane. To keep things consistent, this should always be used
+ * wherever we allocate a buffer based on surface stride and height.
+ *
+ * @param aExtra Optional argument to specify an additional number of trailing
+ *   bytes (useful for creating intermediate surfaces for filters, for
+ *   example).
+ *
+ * @return The result of the multiplication if it is acceptable, or else zero.
+ */
+size_t
+BufferSizeFromStrideAndHeight(int32_t aStride,
+                              int32_t aHeight,
+                              int32_t aExtraBytes = 0);
+
+}
+}
+
+#endif // _MOZILLA_GFX_DATASURFACEHELPERS_H