Remove deprecated string features.

runtime/bin/process_patch.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.
 
 patch class _WindowsCodePageDecoder {
   /* patch */ static String _decodeBytes(List<int> bytes)
       native "SystemEncodingToString";
 }
 
 
@@ skipping 89 matching lines @@
   }
 
   String _windowsArgumentEscape(String argument) {
     var result = argument;
     if (argument.contains('\t') || argument.contains(' ')) {
       // Produce something that the C runtime on Windows will parse
       // back as this string.
 
       // Replace any number of '\' followed by '"' with
       // twice as many '\' followed by '\"'.
-      var backslash = '\\'.charCodeAt(0);
+      var backslash = '\\'.codeUnitAt(0);
       var sb = new StringBuffer();
       var nextPos = 0;
       var quotePos = argument.indexOf('"', nextPos);
       while (quotePos != -1) {
         var numBackslash = 0;
         var pos = quotePos - 1;
-        while (pos >= 0 && argument.charCodeAt(pos) == backslash) {
+        while (pos >= 0 && argument.codeUnitAt(pos) == backslash) {
           numBackslash++;
           pos--;
         }
         sb.add(argument.substring(nextPos, quotePos - numBackslash));
         for (var i = 0; i < numBackslash; i++) {
           sb.add(r'\\');
         }
         sb.add(r'\"');
         nextPos = quotePos + 1;
         quotePos = argument.indexOf('"', nextPos);
       }
       sb.add(argument.substring(nextPos, argument.length));
       result = sb.toString();
 
       // Add '"' at the beginning and end and replace all '\' at
       // the end with two '\'.
       sb = new StringBuffer('"');
       sb.add(result);
       nextPos = argument.length - 1;
-      while (argument.charCodeAt(nextPos) == backslash) {
+      while (argument.codeUnitAt(nextPos) == backslash) {
         sb.add('\\');
         nextPos--;
       }
       sb.add('"');
       result = sb.toString();
     }
 
     return result;
   }
 
@@ skipping 178 matching lines @@
 
 class _ProcessResult implements ProcessResult {
   const _ProcessResult(int this.exitCode,
                        String this.stdout,
                        String this.stderr);
 
   final int exitCode;
   final String stdout;
   final String stderr;
 }