diff -r 000000000000 -r 6474c204b198 gfx/thebes/gfxFontMissingGlyphs.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/thebes/gfxFontMissingGlyphs.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,40 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * 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_FONTMISSINGGLYPHS_H
+#define GFX_FONTMISSINGGLYPHS_H
+
+#include "gfxTypes.h"
+#include "gfxRect.h"
+
+class gfxContext;
+
+/**
+ * This class should not be instantiated. It's just a container
+ * for some helper functions.
+ */
+class gfxFontMissingGlyphs {
+public:
+    /**
+     * Draw hexboxes for a missing glyph.
+     * @param aContext the context to draw to
+     * @param aRect the glyph-box for the glyph that is missing
+     * @param aChar the UTF16 codepoint for the character
+     * @param aAppUnitsPerDevPixel the appUnits to devPixel ratio we're using,
+     *                             (so we can scale glyphs to a sensible size)
+     */
+    static void DrawMissingGlyph(gfxContext    *aContext,
+                                 const gfxRect& aRect,
+                                 uint32_t       aChar,
+                                 uint32_t       aAppUnitsPerDevPixel);
+    /**
+     * @return the desired minimum width for a glyph-box that will allow
+     * the hexboxes to be drawn reasonably.
+     */
+    static gfxFloat GetDesiredMinWidth(uint32_t aChar,
+                                       uint32_t aAppUnitsPerDevUnit);
+};
+
+#endif