Remove deprecated string features.

pkg/webdriver/lib/src/base64decoder.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.
 
 part of webdriver;
 
 /**
  * A simple base64 decoder class, used to decode web browser screenshots
  * returned by WebDriver.
  */
 class Base64Decoder {
 
   static int getVal(String s, pos) {
-    int code = s.charCodeAt(pos);
+    int code = s.codeUnitAt(pos);
     if (code >= 65 && code < (65+26)) { // 'A'..'Z'
       return code - 65;
     } else if (code >= 97 && code < (97+26)) { // 'a'..'z'
       return code - 97 + 26;
     } else if (code >= 48 && code < (48+10)) { // '0'..'9'
       return code - 48 + 52;
     } else if (code == 43) { // '+'
       return 62;
     } else if (code == 47) { // '/'
       return 63;
@@ skipping 21 matching lines @@
             (getVal(s, pos + 2) << 6) | getVal(s, pos+3);
         pos += 4;
         rtn.add((v >> 16 ) & 0xff);
         rtn.add((v >> 8) & 0xff);
         rtn.add(v & 0xff);
       }
     }
     return rtn;
   }
 }