--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/components/desktop/firefox/patches/firefox100-39-cairo-perf.patch	Mon Jan 11 09:27:45 2016 -0800
@@ -0,0 +1,33 @@
+This enables tracking of ARGB values for image masks, since some machines do 
+not use ARGB values. 
+See Mozilla bug #716462 - Performance regression with xBGR visual and no 
+RENDER extension. 
+We would like to try to get this upstream in the future. 
+
+--- mozilla-esr31/gfx/cairo/cairo/src/cairo-xlib-surface.c.orig	2015-06-04 17:42:51.419088049 -0700
++++ mozilla-esr31/gfx/cairo/cairo/src/cairo-xlib-surface.c	2015-06-04 17:42:51.424665839 -0700
+@@ -2325,6 +2325,7 @@
+ 			   cairo_region_t *clip_region)
+ {
+     cairo_image_surface_t *image;
++    cairo_format_masks_t image_masks;
+     cairo_rectangle_int_t extents;
+     cairo_status_t status;
+     int tx, ty;
+@@ -2341,6 +2342,16 @@
+ 	    (image->base.content & CAIRO_CONTENT_ALPHA) == 0)))
+ 	return CAIRO_INT_STATUS_UNSUPPORTED;
+ 
++    if (image->base.backend->type == CAIRO_SURFACE_TYPE_IMAGE) {
++	if (_pixman_format_to_masks (image->pixman_format, &image_masks)) {
++	    if (! ((image_masks.alpha_mask == surface->a_mask || surface->a_mask == 0) &&
++		   (image_masks.red_mask   == surface->r_mask || surface->r_mask == 0) &&
++		   (image_masks.green_mask == surface->g_mask || surface->g_mask == 0) &&
++		   (image_masks.blue_mask  == surface->b_mask || surface->b_mask == 0)))
++		return CAIRO_INT_STATUS_UNSUPPORTED;
++	}
++    }
++
+     if (image->base.backend->type != CAIRO_SURFACE_TYPE_IMAGE) {
+ 	if (image->base.backend->type == CAIRO_INTERNAL_SURFACE_TYPE_SNAPSHOT) {
+ 	    image = (cairo_image_surface_t *) ((cairo_surface_snapshot_t *) image)->target;