Rollback 6bee780067d3c84bfbc387720a26b0eabe7c2357, restore PrintWriter.

pkg/analyzer/test/src/dart/ast/utilities_test.dart

Index: pkg/analyzer/test/src/dart/ast/utilities_test.dart
diff --git a/pkg/analyzer/test/src/dart/ast/utilities_test.dart b/pkg/analyzer/test/src/dart/ast/utilities_test.dart
index d629a83610bcffccf3c60ba0d7b7fc42057b3016..a48fb6e31d99379757daadd4c9ca034d0802eabd 100644
--- a/pkg/analyzer/test/src/dart/ast/utilities_test.dart
+++ b/pkg/analyzer/test/src/dart/ast/utilities_test.dart
@@ -10,6 +10,7 @@ import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/element/element.dart';
+import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/java_engine.dart' show Predicate;
 import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/testing/ast_factory.dart';
@@ -3340,8 +3341,8 @@ class ToSourceVisitorTest extends EngineTestCase {
    * @throws AFE if the visitor does not produce the expected source for the given node
    */
   void _assertSource(String expectedSource, AstNode node) {
-    StringBuffer buffer = new StringBuffer();
-    node.accept(new ToSourceVisitor(buffer));
-    expect(buffer.toString(), expectedSource);
+    PrintStringWriter writer = new PrintStringWriter();
+    node.accept(new ToSourceVisitor(writer));
+    expect(writer.toString(), expectedSource);
   }
 }