Serialize <string> with double quotes

LayoutTests/fast/css/content-language-dynamically-removed.html

Index: LayoutTests/fast/css/content-language-dynamically-removed.html
diff --git a/LayoutTests/fast/css/content-language-dynamically-removed.html b/LayoutTests/fast/css/content-language-dynamically-removed.html
index 6f8da8e4b2f41c9c55deda623465a99a015ae33d..ad5e60c67e9ce8f4a2a6db908360925c46846e84 100644
--- a/LayoutTests/fast/css/content-language-dynamically-removed.html
+++ b/LayoutTests/fast/css/content-language-dynamically-removed.html
@@ -23,14 +23,14 @@ function languageOfNode(id) {
     var element = document.getElementById(id);
     return window.getComputedStyle(element).webkitLocale;
 }
-shouldBeEqualToString("languageOfNode('x')", "'zh'");
-shouldBeEqualToString("languageOfNode('y')", "'ar'");
+shouldBeEqualToString("languageOfNode('x')", '"zh"');
+shouldBeEqualToString("languageOfNode('y')", '"ar"');
 
 var meta = document.getElementById("target");
 var parent = meta.parentNode;
 meta.parentNode.removeChild(meta);
-shouldBeEqualToString("languageOfNode('x')", "'zh'");
-shouldBeEqualToString("languageOfNode('y')", "'ar'");
+shouldBeEqualToString("languageOfNode('x')", '"zh"');
+shouldBeEqualToString("languageOfNode('y')", '"ar"');
 </script>
 </body>
 </html>