Make sure double to DateTime conversion never throws.

tools/dom/src/native_DOMImplementation.dart

Index: tools/dom/src/native_DOMImplementation.dart
diff --git a/tools/dom/src/native_DOMImplementation.dart b/tools/dom/src/native_DOMImplementation.dart
index cd98baf128b56e9773769fd923b8b643330dcc8d..82124d85ab9ebcc3bef92f747409e91f8cff71e2 100644
--- a/tools/dom/src/native_DOMImplementation.dart
+++ b/tools/dom/src/native_DOMImplementation.dart
@@ -7,8 +7,15 @@ part of html;
 class _Utils {
   static double dateTimeToDouble(DateTime dateTime) =>
       dateTime.millisecondsSinceEpoch.toDouble();
-  static DateTime doubleToDateTime(double dateTime) =>
-      new DateTime.fromMillisecondsSinceEpoch(dateTime.toInt());
+  static DateTime doubleToDateTime(double dateTime) {
+    try {
+      return new DateTime.fromMillisecondsSinceEpoch(dateTime.toInt());
+    } catch {
+      // TODO(antonnm): treat exceptions properly in bindings and
+      // find out how to treat NaNs.
+      return null;
+    }
+  }
 
   static List convertToList(List list) {
     // FIXME: [possible optimization]: do not copy the array if Dart_IsArray is fine w/ it.