Update documentation of Performance.timing/navigation

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 10fc224c0d50f57ebc361ac10be9f3e32ab8b26c..2a7bcc7c9a320bf196e62360efa9885390dfaf98 100644
--- a/Source/core/timing/PerformanceTiming.idl
+++ b/Source/core/timing/PerformanceTiming.idl
@@ -28,13 +28,10 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-// http://www.w3.org/TR/navigation-timing/#sec-navigation-timing-interface
-
-// TODO(philipj): This interface been morphed into PerformanceNavigationTiming
-// in the latest spec:
-// https://w3c.github.io/navigation-timing/#sec-PerformanceNavigationTiming
+// https://w3c.github.io/navigation-timing/#the-performancetiming-interface
 
 [
+    Exposed=Window,
     GarbageCollected
 ] interface PerformanceTiming {
     readonly attribute unsigned long long navigationStart;
@@ -58,7 +55,5 @@
     readonly attribute unsigned long long domComplete;
     readonly attribute unsigned long long loadEventStart;
     readonly attribute unsigned long long loadEventEnd;
-
-    // TODO(philipj): This serializer is not defined in the spec.
     serializer = {attribute};
 };