Move frog/leg to lib/compiler/implementation.

frog/leg/diagnostic_listener.dart

Index: frog/leg/diagnostic_listener.dart
===================================================================
--- frog/leg/diagnostic_listener.dart	(revision 5925)
+++ frog/leg/diagnostic_listener.dart	(working copy)
@@ -1,11 +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.
-
-interface DiagnosticListener {
-  // TODO(karlklose): replace cancel with better error reporting mechanism.
-  void cancel([String reason, node, token, instruction, element]);
-  // TODO(karlklose): rename log to something like reportInfo.
-  void log(message);
-  // TODO(karlklose): add reportWarning and reportError to this interface.
-}