Bug 1367299 - Allow -webkit-radial-gradient to be serialized in different way with stylo. r=dholbert

MozReview-Commit-ID: 7hBIf6PkiRa

--HG--
extra : rebase_source : 5ddb9efcfa6e797faf89938e96a60238ccaf3ae1

layout/style/test/stylo-failures.md

@@ -46,8 +46,6 @@ to mochitest command.
 
 ## Need Gecko change
 
-* test_specified_value_serialization.html `-webkit-radial-gradient`: bug 1380259 [1]
-
 ## Unknown / Unsure
 
 ## Ignore

layout/style/test/test_specified_value_serialization.html

@@ -122,13 +122,24 @@
     [ "-webkit-linear-gradient(top left, red, blue)",
       "-webkit-linear-gradient(left top, red, blue)",
       "-webkit-linear-gradient with box corner" ],
-
-    // Radial gradients (should be serialized using modern unprefixed style):
-    [ "-webkit-radial-gradient(contain, red, blue)",
-      "radial-gradient(closest-side, red, blue)",
-      "-webkit-radial-gradient with legacy 'contain' keyword" ],
   ];
 
+  if (!SpecialPowers.DOMWindowUtils.isStyledByServo) {
+    // Radial gradients (should be serialized using modern unprefixed style):
+    backgroundImages.push([
+      "-webkit-radial-gradient(contain, red, blue)",
+      "radial-gradient(closest-side, red, blue)",
+      "-webkit-radial-gradient with legacy 'contain' keyword",
+    ]);
+  } else {
+    // Servo keeps the original prefix form which is closer to other impls.
+    backgroundImages.push([
+      "-webkit-radial-gradient(contain, red, blue)",
+      "-webkit-radial-gradient(center center, closest-side, red, blue)",
+      "-webkit-radial-gradient with legacy 'contain' keyword",
+    ]);
+  }
+
   var frame_container = document.getElementById("display");
   var p = document.createElement("p");
   frame_container.appendChild(p);