Make sure <url>s are being serialized according to spec

third_party/WebKit/LayoutTests/animations/responsive/resources/responsive-test.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /*
 Exported function:
 assertResponsive
 
 Call signature:
 assertResponsive({
@@ skipping 132 matching lines @@
       stateTransitionTests.push({
         applyStateTransition() {
           setState(targets, property, after.state);
         },
         assert() {
           for (var i = 0; i < targets.length; i++) {
             var target = targets[i];
             var expectation = after.expect[i];
             var actual = getComputedStyle(target)[property];
             test(function() {
+              if (/url\(([^\)]*)\)/g.test(expectation.is) && !/url\(\"([^\)]*)\"\)/g.test(expectation.is)) {
+                var url = /url\(([^\)]*)\)/g.exec(expectation.is)[1];
+                expectation.is = 'url(\"' + url + '\")';
+              }
               assert_equals(actual, expectation.is);
             }, `Animation on property <${property}> from [${from}] to [${to}] with ${JSON.stringify(before.state)} changed to ${JSON.stringify(after.state)} at (${expectation.at}) is [${expectation.is}]`);
           }
         },
       });
     });
   });
 
   // Force style recalc to instantiate animations internally.
   getComputedStyle(document.body).color;
@@ skipping 23 matching lines @@
   requestAnimationFrame(function() {
     runPendingResponsiveTests();
     asyncHandle.done()
   });
 });
 
 
 window.assertResponsive = assertResponsive;
 
 })();