Move scanner into pkg/front_end/lib/src/scanner.

pkg/analyzer/lib/src/generated/interner.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.generated.interner;
 
 import 'dart:collection';
 
-/**
- * The interface `Interner` defines the behavior of objects that can intern
- * strings.
- */
-abstract class Interner {
-  /**
-   * Return a string that is identical to all of the other strings that have
-   * been interned that are equal to the given [string].
-   */
-  String intern(String string);
-}
+import 'package:front_end/src/scanner/interner.dart';
+
+export 'package:front_end/src/scanner/interner.dart'
+    show Interner, NullInterner;
 
 /**
  * The class `MappedInterner` implements an interner that uses a map to manage
  * the strings that have been interned.
  */
 class MappedInterner implements Interner {
   /**
    * A table mapping strings to themselves.
    */
   Map<String, String> _table = new HashMap<String, String>();
 
   @override
   String intern(String string) {
     String original = _table[string];
     if (original == null) {
       _table[string] = string;
       return string;
     }
     return original;
   }
 }
-
-/**
- * The class `NullInterner` implements an interner that does nothing (does not
- * actually intern any strings).
- */
-class NullInterner implements Interner {
-  @override
-  String intern(String string) => string;
-}