Rollback 6bee780067d3c84bfbc387720a26b0eabe7c2357, restore PrintWriter.

pkg/analyzer/lib/src/dart/ast/ast.dart

 // Copyright (c) 2014, 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 analyzer.src.dart.ast.ast;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisEngine;
+import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/source.dart' show LineInfo, Source;
 import 'package:analyzer/src/generated/utilities_dart.dart';
 
 /**
  * Two or more string literals that are implicitly concatenated because of being
  * adjacent (separated only by whitespace).
  *
  * While the grammar only allows adjacent strings when all of the strings are of
@@ skipping 902 matching lines @@
     } else {
       if (_propertyMap == null) {
         _propertyMap = new HashMap<String, Object>();
       }
       _propertyMap[name] = value;
     }
   }
 
   @override
   String toSource() {
-    StringBuffer buffer = new StringBuffer();
-    accept(new ToSourceVisitor(buffer));
-    return buffer.toString();
+    PrintStringWriter writer = new PrintStringWriter();
+    accept(new ToSourceVisitor(writer));
+    return writer.toString();
   }
 
   @override
   String toString() => toSource();
 
   /**
    * Make this node the parent of the given [child] node. Return the child node.
    */
   AstNode _becomeParentOf(AstNodeImpl child) {
     if (child != null) {
@@ skipping 10093 matching lines @@
 
   @override
   dynamic/*=E*/ accept/*<E>*/(AstVisitor/*<E>*/ visitor) =>
       visitor.visitYieldStatement(this);
 
   @override
   void visitChildren(AstVisitor visitor) {
     _expression?.accept(visitor);
   }
 }