diff -r 000000000000 -r 6474c204b198 gfx/cairo/dwrite-font-match-robustness.patch
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/cairo/dwrite-font-match-robustness.patch	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,26 @@
+From: Robert O'Callahan <robert@ocallahan.org>
+Bug 717178. Part 1: Don't crash when passing a nil scaled-font to _name_tables_match. r=jfkthame
+
+diff --git a/gfx/cairo/cairo/src/cairo-dwrite-font.cpp b/gfx/cairo/cairo/src/cairo-dwrite-font.cpp
+--- a/gfx/cairo/cairo/src/cairo-dwrite-font.cpp
++++ b/gfx/cairo/cairo/src/cairo-dwrite-font.cpp
+@@ -1489,17 +1489,18 @@ static cairo_bool_t
+     unsigned long size1;
+     unsigned long size2;
+     cairo_int_status_t status1;
+     cairo_int_status_t status2;
+     unsigned char *buffer1;
+     unsigned char *buffer2;
+     cairo_bool_t result = false;
+ 
+-    if (!font1->backend->load_truetype_table ||
++    if (!font1->backend || !font2->backend ||
++        !font1->backend->load_truetype_table ||
+         !font2->backend->load_truetype_table)
+         return false;
+ 
+     status1 = font1->backend->load_truetype_table (font1,
+                                                    TT_TAG_name, 0, NULL, &size1);
+     status2 = font2->backend->load_truetype_table (font2,
+                                                    TT_TAG_name, 0, NULL, &size2);
+     if (status1 || status2)