diff -Nru firefox-44.0+build3/debian/changelog firefox-44.0+build3/debian/changelog
--- firefox-44.0+build3/debian/changelog	2016-01-25 16:47:20.000000000 +0100
+++ firefox-44.0+build3/debian/changelog	2016-01-28 14:21:18.000000000 +0100
@@ -1,3 +1,10 @@
+firefox (44.0+build3-0ubuntu3) xenial; urgency=medium
+
+  * Re-establish equivalence between gfxImageFormat and cairo_format_t.
+    (LP: #1538724)
+
+ -- Dariusz Gadomski <dariusz.gadomski@canonical.com>  Thu, 28 Jan 2016 14:20:47 +0100
+
 firefox (44.0+build3-0ubuntu2) xenial; urgency=medium
 
   * Fix webrtc build on AArch64.
diff -Nru firefox-44.0+build3/debian/patches/lp1538724.patch firefox-44.0+build3/debian/patches/lp1538724.patch
--- firefox-44.0+build3/debian/patches/lp1538724.patch	1970-01-01 01:00:00.000000000 +0100
+++ firefox-44.0+build3/debian/patches/lp1538724.patch	2016-01-28 14:25:24.000000000 +0100
@@ -0,0 +1,52 @@
+Description: Re-establish equivalence between gfxImageFormat and cairo_format_t.
+ It would be nice to add static assertions for this equivalence but I don't want
+ to have to include cairo.h in gfxTypes.h. (Indeed, that's why
+ gfxImageFormatToCairoFormat and gfxCairoFormatToImageFormat are macros in the
+ first place).
+ .
+ firefox (44.0+build3-0ubuntu3) xenial; urgency=medium
+ .
+   * Re-establish equivalence between gfxImageFormat and cairo_format_t.
+     (LP: #1538724)
+Author: Nicholas Nethercote <nnethercote@mozilla.com>
+Bug-Ubuntu: https://bugs.launchpad.net/bugs/1538724
+Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1222171
+Origin: upstream, https://hg.mozilla.org/try/rev/79382e397d1d
+
+--- firefox-44.0+build3.orig/gfx/thebes/gfxTypes.h
++++ firefox-44.0+build3/gfx/thebes/gfxTypes.h
+@@ -47,24 +47,28 @@ enum class gfxBreakPriority {
+ /**
+   * The format for an image surface. For all formats with alpha data, 0
+   * means transparent, 1 or 255 means fully opaque.
++  *
++  * XXX: it's vital that the values here match the values in cairo_format_t,
++  * otherwise gfxCairoFormatToImageFormat() and gfxImageFormatToCairoFormat()
++  * won't work.
+   */
+ enum class gfxImageFormat {
+-  ARGB32, ///< ARGB data in native endianness, using premultiplied alpha
+-  RGB24,  ///< xRGB data in native endianness
+-  A8,     ///< Only an alpha channel
+-  RGB16_565,  ///< RGB_565 data in native endianness
++  ARGB32    = 0, ///< ARGB data in native endianness, using premultiplied alpha
++  RGB24     = 1, ///< xRGB data in native endianness
++  A8        = 2, ///< Only an alpha channel
++  RGB16_565 = 4, ///< RGB_565 data in native endianness
+   Unknown
+ };
+ 
+ // XXX: temporary
+ // This works because the gfxImageFormat enum is defined so as to match the
+-// _cairo_format enum.
++// cairo_format_t enum.
+ #define gfxCairoFormatToImageFormat(aFormat) \
+     ((gfxImageFormat)aFormat)
+ 
+ // XXX: temporary
+ // This works because the gfxImageFormat enum is defined so as to match the
+-// _cairo_format enum.
++// cairo_format_t enum.
+ #define gfxImageFormatToCairoFormat(aFormat) \
+     ((cairo_format_t)aFormat)
+ 
diff -Nru firefox-44.0+build3/debian/patches/series firefox-44.0+build3/debian/patches/series
--- firefox-44.0+build3/debian/patches/series	2016-01-25 16:45:25.000000000 +0100
+++ firefox-44.0+build3/debian/patches/series	2016-01-28 14:23:10.000000000 +0100
@@ -26,3 +26,4 @@
 disable-geo-specific-search-defaults-for-us.patch
 cleanup-geo-specific-search-defaults.patch
 webrtc-aarch64.diff
+lp1538724.patch