Move diagnostic_listener.dart and messages.dart to the diagnostics folder

pkg/compiler/lib/src/diagnostic_listener.dart

Index: pkg/compiler/lib/src/diagnostic_listener.dart
diff --git a/pkg/compiler/lib/src/diagnostic_listener.dart b/pkg/compiler/lib/src/diagnostic_listener.dart
deleted file mode 100644
index cdcef75fb0eb3d83d3e034e91efff69c31ed2bc1..0000000000000000000000000000000000000000
--- a/pkg/compiler/lib/src/diagnostic_listener.dart
+++ /dev/null
@@ -1,40 +0,0 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library dart2js.diagnostic_listener;
-
-import 'diagnostics/source_span.dart' show
-    SourceSpan;
-import 'diagnostics/spannable.dart' show
-    Spannable;
-import 'elements/elements.dart' show
-    Element;
-import 'messages.dart';
-
-abstract class DiagnosticListener {
-  // TODO(karlklose): rename log to something like reportInfo.
-  void log(message);
-
-  void internalError(Spannable spannable, message);
-
-  SourceSpan spanFromSpannable(Spannable node);
-
-  void reportError(Spannable node, MessageKind errorCode,
-                   [Map arguments = const {}]);
-
-  void reportWarning(Spannable node, MessageKind errorCode,
-                     [Map arguments = const {}]);
-
-  void reportHint(Spannable node, MessageKind errorCode,
-                  [Map arguments = const {}]);
-
-  void reportInfo(Spannable node, MessageKind errorCode,
-                  [Map arguments = const {}]);
-
-  // TODO(ahe): We should not expose this here.  Perhaps a
-  // [SourceSpan] should implement [Spannable], and we should have a
-  // way to construct a [SourceSpan] from a [Spannable] and an
-  // [Element].
-  withCurrentElement(Element element, f());
-}