Fix errors caused by missing argument checking

runtime/bin/socket_impl.dart

Index: runtime/bin/socket_impl.dart
diff --git a/runtime/bin/socket_impl.dart b/runtime/bin/socket_impl.dart
index 3cd2c770f1cc6a8b7de41ace2b18d256f6beb8f4..08f24d01937210c1a58fa80d1131bf6cfbb8c9b8 100644
--- a/runtime/bin/socket_impl.dart
+++ b/runtime/bin/socket_impl.dart
@@ -391,6 +391,10 @@ class _Socket extends _SocketBase implements Socket {
   _readList(List<int> buffer, int offset, int bytes) native "Socket_ReadList";
 
   int writeList(List<int> buffer, int offset, int bytes) {
+    if (buffer is! List || offset is! int || bytes is! int) {
+      throw new ArgumentError(
+          "Invalid arguments to writeList on Socket");
+    }
     if (!_closed) {
       if (bytes == 0) {
         return 0;