Issue dev_compiler@443. Clone beginToken.

pkg/analyzer/test/generated/utilities_test.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.test.generated.utilities_test;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
@@ skipping 260 matching lines @@
   }
 
   void test_visitCompilationUnit_directive() {
     _assertCloneUnit('library l;');
   }
 
   void test_visitCompilationUnit_directive_declaration() {
     _assertCloneUnit('library l;  var a;');
   }
 
+  void test_visitCompilationUnit_directive_withComment() {
+    _assertCloneUnit(r'''
+/// aaa
+/// bbb
+library l;''');
+  }
+
   void test_visitCompilationUnit_empty() {
     _assertCloneUnit('');
   }
 
   void test_visitCompilationUnit_script() {
     _assertCloneUnit('#!/bin/dartvm');
   }
 
   void test_visitCompilationUnit_script_declaration() {
     _assertCloneUnit('#!/bin/dartvm \n var a;');
@@ skipping 4006 matching lines @@
   }
 
   void test_get_added() {
     TokenMap tokenMap = new TokenMap();
     Token key = TokenFactory.tokenFromType(TokenType.AT);
     Token value = TokenFactory.tokenFromType(TokenType.AT);
     tokenMap.put(key, value);
     expect(tokenMap.get(key), same(value));
   }
 }