Remove deprecated string features.

sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirror.dart

 // Copyright (c) 2012, 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 mirrors_dart2js;
 
 import 'dart:async';
 import 'dart:collection' show LinkedHashMap;
 import 'dart:io';
 import 'dart:uri';
@@ skipping 670 matching lines @@
     if (length == 0) return 0;
 
     var sourceFile = _script.file as SourceFile;
     if (sourceFile != null) {
       return sourceFile.getColumn(sourceFile.getLine(offset), offset) + 1;
     }
     int index = offset - 1;
     var columnNumber = 0;
     while (0 <= index && index < sourceText.length) {
       columnNumber++;
-      var charCode = sourceText.charCodeAt(index);
-      if (charCode == $CR || charCode == $LF) {
+      var codeUnit = sourceText.codeUnitAt(index);
+      if (codeUnit == $CR || codeUnit == $LF) {
         break;
       }
       index--;
     }
     return columnNumber;
   }
 
   int get column {
     if (_column == null) {
       _column = _computeColumn();
@@ skipping 1030 matching lines @@
       return new Future.immediate(
           new Dart2JsStringConstantMirror.fromString(mirrors, text));
     } else if (fieldName == 'trimmedText') {
       return new Future.immediate(
           new Dart2JsStringConstantMirror.fromString(mirrors, trimmedText));
     }
     // TODO(johnniwinther): Which exception/error should be thrown here?
     throw new UnsupportedError('InstanceMirror does not have a reflectee');
   }
 }