Bug 1420229 - Run formautofill xpcshell tests in headless mode;r=bdahl This is needed because DOMParser is invoked on some fixture HTML that contains an <svg> element (Walmart/Payment.html). When this happens **and** there is a declaration for `color: MenuText` in a UA stylesheet (which is added in the next changeset), there is a graphics crash. This is fixed in the new headless mode, so this changeset forces the directory to run in it. MozReview-Commit-ID: 9T8eFOW4xoz

--- a/browser/extensions/formautofill/test/unit/xpcshell.ini
+++ b/browser/extensions/formautofill/test/unit/xpcshell.ini
@@ -1,10 +1,11 @@
 [DEFAULT]
 firefox-appdir = browser
+headless = true
 head = head.js
 support-files =
   ../fixtures/**
 
 [heuristics/test_basic.js]
 [heuristics/test_cc_exp.js]
 [heuristics/test_de_fields.js]
 [heuristics/test_multiple_section.js]