Add access the Message in CompilerDiagnostics.report.

pkg/compiler/lib/compiler_new.dart

Index: pkg/compiler/lib/compiler_new.dart
diff --git a/pkg/compiler/lib/compiler_new.dart b/pkg/compiler/lib/compiler_new.dart
index 3ec05ec39b2df18f6ccb419905ccd4f5c695624f..7d4ef18f266db99c31d6fc25491615ecc16c94ab 100644
--- a/pkg/compiler/lib/compiler_new.dart
+++ b/pkg/compiler/lib/compiler_new.dart
@@ -67,7 +67,12 @@ abstract class CompilerDiagnostics {
   /// zero-based character offsets from the beginning of the compilation unit.
   /// [message] is the diagnostic message, and [kind] indicates indicates what
   /// kind of diagnostic it is.
-  void report(Uri uri, int begin, int end, String message, Diagnostic kind);
+  ///
+  /// Experimental: [code] gives access to an id for the messages. Currently it
+  /// is the [Message] used to create the diagnostic, if available, from which
+  /// the [MessageKind] is accessible.
+  void report(var code,
+              Uri uri, int begin, int end, String text, Diagnostic kind);
 }
 
 /// Information resulting from the compilation.