bindings: Supports serializer for PerformanceTiming.

Source/core/timing/PerformanceTiming.idl

Index: Source/core/timing/PerformanceTiming.idl
diff --git a/Source/core/timing/PerformanceTiming.idl b/Source/core/timing/PerformanceTiming.idl
index 0485ffb256cd6b31ec30ccf19254407afdd2b09d..cff49066d46c5eba91bf63ba6b594b35f24bb7d0 100644
--- a/Source/core/timing/PerformanceTiming.idl
+++ b/Source/core/timing/PerformanceTiming.idl
@@ -28,7 +28,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-// See: http://dev.w3.org/2006/webapi/WebTiming/
+// See: https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/NavigationTiming/Overview.html#sec-navigation-timing-interface
 [
     GarbageCollected
 ] interface PerformanceTiming {
@@ -53,4 +53,6 @@
     readonly attribute unsigned long long domComplete;
     readonly attribute unsigned long long loadEventStart;
     readonly attribute unsigned long long loadEventEnd;
+
+    serializer = {attribute};
 };