diff -r 000000000000 -r 6474c204b198 gfx/src/nsSize.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/src/nsSize.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,79 @@
+/* -*- 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 NSSIZE_H
+#define NSSIZE_H
+
+#include "nsCoord.h"
+#include "mozilla/gfx/BaseSize.h"
+#include "mozilla/gfx/Point.h"
+
+// Maximum allowable size
+#define NS_MAXSIZE nscoord_MAX
+
+struct nsIntSize;
+typedef nsIntSize gfxIntSize;
+
+struct nsSize : public mozilla::gfx::BaseSize<nscoord, nsSize> {
+  typedef mozilla::gfx::BaseSize<nscoord, nsSize> Super;
+
+  nsSize() : Super() {}
+  nsSize(nscoord aWidth, nscoord aHeight) : Super(aWidth, aHeight) {}
+
+  inline nsIntSize ScaleToNearestPixels(float aXScale, float aYScale,
+                                        nscoord aAppUnitsPerPixel) const;
+  inline nsIntSize ToNearestPixels(nscoord aAppUnitsPerPixel) const;
+
+  // Converts this size from aFromAPP, an appunits per pixel ratio, to aToAPP.
+  inline nsSize ConvertAppUnits(int32_t aFromAPP, int32_t aToAPP) const;
+};
+
+struct nsIntSize : public mozilla::gfx::BaseSize<int32_t, nsIntSize> {
+  typedef mozilla::gfx::BaseSize<int32_t, nsIntSize> Super;
+
+  nsIntSize() : Super() {}
+  nsIntSize(int32_t aWidth, int32_t aHeight) : Super(aWidth, aHeight) {}
+
+  inline nsSize ToAppUnits(nscoord aAppUnitsPerPixel) const;
+  mozilla::gfx::IntSize ToIntSize() const
+  {
+    return mozilla::gfx::IntSize(width, height);
+  };
+};
+
+inline nsIntSize
+nsSize::ScaleToNearestPixels(float aXScale, float aYScale,
+                             nscoord aAppUnitsPerPixel) const
+{
+  return nsIntSize(
+      NSToIntRoundUp(NSAppUnitsToDoublePixels(width, aAppUnitsPerPixel) * aXScale),
+      NSToIntRoundUp(NSAppUnitsToDoublePixels(height, aAppUnitsPerPixel) * aYScale));
+}
+
+inline nsIntSize
+nsSize::ToNearestPixels(nscoord aAppUnitsPerPixel) const
+{
+  return ScaleToNearestPixels(1.0f, 1.0f, aAppUnitsPerPixel);
+}
+
+inline nsSize
+nsSize::ConvertAppUnits(int32_t aFromAPP, int32_t aToAPP) const {
+  if (aFromAPP != aToAPP) {
+    nsSize size;
+    size.width = NSToCoordRound(NSCoordScale(width, aFromAPP, aToAPP));
+    size.height = NSToCoordRound(NSCoordScale(height, aFromAPP, aToAPP));
+    return size;
+  }
+  return *this;
+}
+
+inline nsSize
+nsIntSize::ToAppUnits(nscoord aAppUnitsPerPixel) const
+{
+  return nsSize(NSIntPixelsToAppUnits(width, aAppUnitsPerPixel),
+                NSIntPixelsToAppUnits(height, aAppUnitsPerPixel));
+}
+
+#endif /* NSSIZE_H */