dart2js: Capture typedef arguments once

pkg/js_ast/lib/src/printer.dart

 // 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.
 
 part of js_ast;
 
 typedef String Renamer(Name);
 
 class JavaScriptPrintingOptions {
   final bool shouldCompressOutput;
@@ skipping 43 matching lines @@
 class SimpleJavaScriptPrintingContext extends JavaScriptPrintingContext {
   final StringBuffer buffer = new StringBuffer();
 
   void emit(String string) {
     buffer.write(string);
   }
 
   String getText() => buffer.toString();
 }
 
+String DebugPrint(Node node) {
+  JavaScriptPrintingOptions options = new JavaScriptPrintingOptions();
+  SimpleJavaScriptPrintingContext context =
+      new SimpleJavaScriptPrintingContext();
+  Printer printer = new Printer(options, context);
+  printer.visit(node);
+  return context.getText();
+}
+
 class Printer implements NodeVisitor {
   final JavaScriptPrintingOptions options;
   final JavaScriptPrintingContext context;
   final bool shouldCompressOutput;
   final DanglingElseVisitor danglingElseVisitor;
   final LocalNamer localNamer;
 
   int _charCount = 0;
   bool inForInit = false;
   bool atStatementBegin = false;
@@ skipping 1408 matching lines @@
     }
   }
 
   EnterExitNode exitNode(JavaScriptPrintingContext context, int position) {
     // Enter must happen before exit.
     addToNode(context, position);
     context.exitNode(node, startPosition, position, closingPosition);
     return parent;
   }
 }