Refactor Date implementation in VM.

lib/compiler/implementation/lib/js_helper.dart

Index: lib/compiler/implementation/lib/js_helper.dart
diff --git a/lib/compiler/implementation/lib/js_helper.dart b/lib/compiler/implementation/lib/js_helper.dart
index 41c663ca082d9bc6e611831d4aac0799ac2da9c2..0ffe79e14958de46831f6f729632c358809e392c 100644
--- a/lib/compiler/implementation/lib/js_helper.dart
+++ b/lib/compiler/implementation/lib/js_helper.dart
@@ -489,7 +489,7 @@ class Primitives {
       value = JS('num', @'new Date(#, #, #, #, #, #, #).valueOf()',
                  years, jsMonth, day, hours, minutes, seconds, milliseconds);
     }
-    if (value.isNaN()) throw new IllegalArgumentException('');
+    if (value.isNaN()) throw new IllegalArgumentException();
     if (years <= 0 || years < 100) return patchUpY2K(value, years, isUtc);
     return value;
   }