--- a/layout/style/test/test_font_loading_api.html
+++ b/layout/style/test/test_font_loading_api.html
@@ -401,19 +401,16 @@ function runTest() {
         });
         return familyTests;
       });
     });
     return p;
 
   }).then(function() {
 
-    // XXX Disabled this sub-test due to intermittent failures (bug 1076803).
-    return;
-
     // (TEST 18) Test passing valid url() source strings to the FontFace
     // constructor.
     var p = Promise.resolve();
     sourceWindows.forEach(function({ win, what }) {
       p = p.then(function() {
         var srcTests = Promise.resolve();
         gCSSFontFaceDescriptors.src.values.forEach(function(aSrc) {
           srcTests = srcTests.then(function() {