Fix off-by-one error in https://code.google.com/p/dart/source/detail?r=45153

sdk/lib/convert/html_escape.dart

 // Copyright (c) 2013, 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 dart.convert;
 
 /**
  * A `String` converter that converts characters to HTML entities.
  *
  * This is intended to sanitice text before inserting the text into an HTML
@@ skipping 164 matching lines @@
     StringBuffer result = null;
     for (int i = start; i < end; i++) {
       var ch = text[i];
       String replacement = null;
       switch (ch) {
         case '&': replacement = '&amp;'; break;
         case '"': if (mode.escapeQuot) replacement = '&quot;'; break;
         case "'": if (mode.escapeApos) replacement = '&#39;'; break;
         case '<': if (mode.escapeLtGt) replacement = '&lt;'; break;
         case '>': if (mode.escapeLtGt) replacement = '&gt;'; break;
-        case '/': if (mode.escapeSlash) replacement = '&#46;'; break;
+        case '/': if (mode.escapeSlash) replacement = '&#47;'; break;
       }
       if (replacement != null) {
         if (result == null) result = new StringBuffer();
         if (i > start) result.write(text.substring(start, i));
         result.write(replacement);
         start = i + 1;
       }
     }
     if (result == null) return null;
     if (end > start) result.write(text.substring(start, end));
@@ skipping 19 matching lines @@
     if(val == null) {
       _sink.addSlice(chunk, start, end, isLast);
     } else {
       _sink.add(val);
       if (isLast) _sink.close();
     }
   }
 
   void close() => _sink.close();
 }