Layout Tests: Remove stringifyDOMObject() helper

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

Index: third_party/WebKit/LayoutTests/resources/js-test.js
diff --git a/third_party/WebKit/LayoutTests/resources/js-test.js b/third_party/WebKit/LayoutTests/resources/js-test.js
index 0419bca488ed8250065579d5c4db3b27385c390b..77b85c369afad00928e5247f88baeb045c307412 100644
--- a/third_party/WebKit/LayoutTests/resources/js-test.js
+++ b/third_party/WebKit/LayoutTests/resources/js-test.js
@@ -216,23 +216,6 @@ function stringify(v)
     else return "" + v;
 }
 
-// Stringifies a DOM object.  This function stringifies not only own properties
-// but also DOM attributes which are on a prototype chain.  Note that
-// JSON.stringify only stringifies own properties.
-function stringifyDOMObject(object)
-{
-    function deepCopy(src) {
-        if (typeof src != "object")
-            return src;
-        var dst = Array.isArray(src) ? [] : {};
-        for (var property in src) {
-            dst[property] = deepCopy(src[property]);
-        }
-        return dst;
-    }
-    return JSON.stringify(deepCopy(object));
-}
-
 function evalAndLog(_a, _quiet)
 {
   if (typeof _a != "string")