--- firefox-68.0.1/gfx/2d/HelpersCairo.h.old	2019-07-17 20:51:26.000000000 +0000
+++ firefox-68.0.1/gfx/2d/HelpersCairo.h	2019-08-10 11:38:36.047380153 +0000
@@ -147,7 +147,7 @@
     case SurfaceFormat::R5G6B5_UINT16:
       return CAIRO_FORMAT_RGB16_565;
     default:
-      gfxCriticalError() << "Unknown image format " << (int)format;
+      //gfxCriticalError() << "Unknown image format " << (int)format;
       return CAIRO_FORMAT_ARGB32;
   }
 }