Base JavaScript code position computation on JavaScript tracer.

pkg/compiler/lib/src/js/js_debug.dart

 // Copyright (c) 2015, 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.
 
 /// Helper for debug JS nodes.
 
 library js.debug;
 
 import 'package:js_ast/js_ast.dart';
-import '../util/util.dart' show Indentation, Tagging;
+
+import '../io/code_output.dart' show
+    BufferedCodeOutput;
+import '../util/util.dart' show
+    Indentation,
+    Tagging;
 
 /// Unparse the JavaScript [node].
 String nodeToString(Node node) {
   JavaScriptPrintingOptions options = new JavaScriptPrintingOptions(
       shouldCompressOutput: true,
       preferSemicolonToNewlineInMinifiedOutput: true);
   LenientPrintingContext printingContext =
       new LenientPrintingContext();
   new Printer(options, printingContext).visit(node);
   return printingContext.getText();
@@ skipping 29 matching lines @@
    * Pretty-prints given node tree into string.
    */
   static String prettyPrint(Node node) {
     var p = new DebugPrinter();
     node.accept(p);
     return p.sb.toString();
   }
 }
 
 /// Simple printing context that doesn't throw on errors.
-class LenientPrintingContext extends SimpleJavaScriptPrintingContext {
+class LenientPrintingContext extends SimpleJavaScriptPrintingContext
+    implements BufferedCodeOutput {
   @override
   void error(String message) {
     buffer.write('>>$message<<');
   }
 }