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

third_party/WebKit/LayoutTests/fast/js/resources/image-preload-helper.js

 // This is used by several tests to help get images reliably preloaded.
 
 // Given a node, loads all urls specified in style declarations
 // attached to the node or it's decendants.
 // imageCount specifies the number of images we expect to find (to try to add some
 // protection against brittleness due to imperfect url parsing, since other missing a preload
 // will typically result in a test that fails only occasionally).
 // If failPattern is specified, then any url that matches the regex
 // will be expected to fail to load.
 function preloadImagesFromStyle(rootNode, imageCount, onComplete, failPattern) {
     var basePath = location.href.substring(0, location.href.lastIndexOf('/') + 1);
     var nodes = rootNode.querySelectorAll('[style]');
     var imagesToLoad = [];
     var seenUrls = {};
     for (var i = 0; i < nodes.length; i++) {
-        var urls = nodes[i].style.cssText.split(/url\w*\(([^)]*)\)/);
+        var urls = nodes[i].style.cssText.split(/url\w*\(\"([^)]*)\"\)/);
         for (var j = 1; j < urls.length; j += 2) {
             // Attempt to convert URL to a relative path in order to have deterministic error messages.
             var url = urls[j];
             if (url.indexOf(basePath) == 0)
                 url = url.substring(basePath.length);
 
             var error = false;
             if (failPattern && failPattern.test(url))
                 error = true;
             if (url in seenUrls)
@@ skipping 38 matching lines @@
     }
 
     for (var i = 0; i < imagesToLoad.length; i++) {
         var img = new Image();
         var expectError = imagesToLoad[i].error;
         img.addEventListener('load', onImageLoad.bind(undefined, imagesToLoad[i].url, !expectError));
         img.addEventListener('error', onImageLoad.bind(undefined, imagesToLoad[i].url, !!expectError));
         img.src = imagesToLoad[i].url;
     }
 }