bindings: Fixes layouttests when moving attributes to prototype chains.

LayoutTests/http/tests/misc/performance-memory-in-dedicated-worker.html

Index: LayoutTests/http/tests/misc/performance-memory-in-dedicated-worker.html
diff --git a/LayoutTests/http/tests/misc/performance-memory-in-dedicated-worker.html b/LayoutTests/http/tests/misc/performance-memory-in-dedicated-worker.html
index 0fb76ae046de8ed21d954da830faabe0e1826621..f37a6be0e699f3a34ac6381edf4e4fd3fc84c4b2 100644
--- a/LayoutTests/http/tests/misc/performance-memory-in-dedicated-worker.html
+++ b/LayoutTests/http/tests/misc/performance-memory-in-dedicated-worker.html
@@ -11,7 +11,10 @@
 var tests = [
   '"performance" in self;',
   '"memory" in self.performance;',
-  'JSON.stringify(self.performance.memory);',
+  ('JSON.stringify(' +
+   '{jsHeapSizeLimit: self.performance.memory.jsHeapSizeLimit,' +
+   ' totalJSHeapSize: self.performance.memory.totalJSHeapSize,' +
+   ' usedJSHeapSize: self.performance.memory.usedJSHeapSize});')
 ];
 
 var t = async_test('window.performance.memory in dedicated workers');