Add access the Message in CompilerDiagnostics.report.

tests/compiler/dart2js/bad_output_io_test.dart

Index: tests/compiler/dart2js/bad_output_io_test.dart
diff --git a/tests/compiler/dart2js/bad_output_io_test.dart b/tests/compiler/dart2js/bad_output_io_test.dart
index ad2b0b9c5ee473cb129ee74996668de81d47e2f0..7815b59c524293be090a58b7d854e30b945e1ed0 100644
--- a/tests/compiler/dart2js/bad_output_io_test.dart
+++ b/tests/compiler/dart2js/bad_output_io_test.dart
@@ -38,13 +38,13 @@ class CollectingFormattingDiagnosticHandler
   }
 
   @override
-  void report(Uri uri, int begin, int end, String message, kind) {
+  void report(var code, Uri uri, int begin, int end, String message, kind) {
     messages.add([message, kind]);
   }
 
   @override
   void call(Uri uri, int begin, int end, String message, kind) {
-    report(uri, begin, end, message, kind);
+    report(null, uri, begin, end, message, kind);
   }
 
   String prefixMessage(String message, Diagnostic kind) {