Issue 250: Allow for GNU formatted errors

compiler/java/com/google/dart/compiler/ast/viz/BaseASTWriter.java

 // Copyright (c) 2011, 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.
 
 package com.google.dart.compiler.ast.viz;
 
 import java.io.File;
 import java.util.List;
 
 import com.google.dart.compiler.ast.DartArrayAccess;
@@ skipping 516 matching lines @@
 
     @Override
     public Object visitSwitchStatement(DartSwitchStatement node) {
       write("DartSwitchStatement", node);
       visitChildren(node);
       return null;
     }
 
     @Override
     public Object visitSyntheticErrorExpression(DartSyntheticErrorExpression node) {
-      write("DartSyntheticErrorExpression", node);
+      write("DartSyntheticErrorExpression(", node, node.getTokenString() + ")");
       visitChildren(node);
       return null;
     }
 
     @Override
     public Object visitSyntheticErrorStatement(DartSyntheticErrorStatement node) {
       write("DartSyntheticErrorStatement", node);
       visitChildren(node);
       return null;
     }
@@ skipping 98 matching lines @@
     }
 
     @Override
     public Object visitRedirectConstructorInvocation(DartRedirectConstructorInvocation node) {
       write("DartRedirectConstructorInvocation", node);
       visitChildren(node);
       return null;
     }
   }
 }