Properly parse native-code V8 frames.

test/frame_test.dart

Index: test/frame_test.dart
diff --git a/test/frame_test.dart b/test/frame_test.dart
index 01177f0d7125f64eb1b7ff43dea6b4f292fbba1f..809822a6db0f66ad5f3fb178dfc1c9b1abbf540b 100644
--- a/test/frame_test.dart
+++ b/test/frame_test.dart
@@ -149,6 +149,15 @@ void main() {
       expect(frame.member, equals('<fn>'));
     });
 
+    test('parses a native stack frame correctly', () {
+      var frame = new Frame.parseV8(
+          "    at Object.stringify (native)");
+      expect(frame.uri, Uri.parse('native'));
+      expect(frame.line, isNull);
+      expect(frame.column, isNull);
+      expect(frame.member, equals('Object.stringify'));
+    });
+
     test('parses a stack frame with [as ...] correctly', () {
       // Ignore "[as ...]", since other stack trace formats don't support a
       // similar construct.