commit ff13efe458e7786d8c810342d25a6ba8e90a422b
Author: Christoph Moench-Tegeder <cmt@FreeBSD.org>

    based on BMO 1269654
    
    : https://bugzilla.mozilla.org/show_bug.cgi?id=1269654#c5
    : https://bug1269654.bmoattachments.org/attachment.cgi?id=8749234
    : handle big-endian formats in Cairo format conversions
    :
    : HG changeset patch
    : User Lee Salzman <lsalzman@mozilla.com>
    : Date 1462463631 14400
    :      Thu May 05 11:53:51 2016 -0400
    : Node ID 8da374804a09977c8f89af5e6e0cb37cb074595d
    : Parent  29662e28a9c93ac67ee0b8ddfb65a9f29bbf73f5
    : handle big-endian formats in Cairo format conversions

diff --git gfx/2d/HelpersCairo.h gfx/2d/HelpersCairo.h
index a10e01bdd62b..f2007ee189fc 100644
--- gfx/2d/HelpersCairo.h
+++ gfx/2d/HelpersCairo.h
@@ -185,7 +185,11 @@ static inline cairo_content_t GfxFormatToCairoContent(SurfaceFormat format) {
     case SurfaceFormat::A8:
       return CAIRO_CONTENT_ALPHA;
     default:
-      gfxCriticalError() << "Unknown image content format " << (int)format;
+      if (format == SurfaceFormat::B8G8R8X8) {
+        return CAIRO_CONTENT_COLOR;
+      } else if (format != SurfaceFormat::B8G8R8A8) {
+        gfxCriticalError() << "Unknown image content format " << (int)format;
+      }
       return CAIRO_CONTENT_COLOR_ALPHA;
   }
 }