Remove deprecated string features.

sdk/lib/_internal/compiler/implementation/scanner/byte_strings.dart

 // Copyright (c) 2011, 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.
 
 /**
  * An abstract string representation.
  */
 abstract class ByteString extends Iterable<int> implements SourceString {
   final List<int> bytes;
   final int offset;
@@ skipping 57 matching lines @@
 
   Iterator<int> get iterator => new AsciiStringIterator(bytes);
 
   SourceString copyWithoutQuotes(int initial, int terminal) {
     return new AsciiString(bytes, offset + initial,
                            length - initial - terminal);
   }
 
 
   static AsciiString fromString(String string) {
-    List<int> bytes = string.charCodes;
+    List<int> bytes = string.codeUnits;
     return AsciiString.of(bytes, 0, bytes.length);
   }
 }
 
 
 class AsciiStringIterator implements Iterator<int> {
   final List<int> bytes;
   int offset;
   final int end;
   int _current;
@@ skipping 56 matching lines @@
  * A ByteString-valued token.
  */
 class ByteStringToken extends Token {
   final ByteString value;
 
   ByteStringToken(PrecedenceInfo info, ByteString this.value, int charOffset)
     : super(info, charOffset);
 
   String toString() => value.toString();
 }