adding HtmlEscape to dart:convert

pkg/intl/lib/bidi_formatter.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.
 
 part of intl;
 
 /**
  * Bidi stands for Bi-directional text.
  * According to [Wikipedia](http://en.wikipedia.org/wiki/Bi-directional_text):
  * Bi-directional text is text containing text in both text directionalities,
@@ skipping 68 matching lines @@
       contextDirection = TextDirection.UNKNOWN, _alwaysSpan = alwaysSpan;
 
   /** Is true if the known context direction for this formatter is RTL. */
   bool get isRTL => contextDirection == TextDirection.RTL;
 
   /**
    * Escapes HTML-special characters of [text] so that the result can be
    * included verbatim in HTML source code, either in an element body or in an
    * attribute value.
    */
-  String htmlEscape(String text) {
-    // TODO(alanknight): This is copied into here directly to avoid having a
-    // dependency on the htmlescape library, which is difficult to do in a way
-    // that's compatible with both package: links and direct links in the SDK.
-    // Once pub is used in test.dart (Issue #4968) this should be removed.
-    // TODO(efortuna): A more efficient implementation.
-    return text.replaceAll("&", "&")
-        .replaceAll("<", "&lt;")
-        .replaceAll(">", "&gt;")
-        .replaceAll('"', "&quot;")
-        .replaceAll("'", "&apos;");
-  }
+  @deprecated
+  String htmlEscape(String text) => HTML_ESCAPE.convert(text);
 
   /**
    * Formats a string of a given (or estimated, if not provided)
    * [direction] for use in HTML output of the context directionality, so
    * an opposite-directionality string is neither garbled nor garbles what
    * follows it.
    * If the input string's directionality doesn't match the context
    * directionality, we wrap it with a `span` tag and add a `dir` attribute
    * (either "dir=rtl" or "dir=ltr").
    * If alwaysSpan was true when constructing the formatter, the input is always
    * wrapped with `span` tag, skipping the dir attribute when it's not needed.
    *
    * If [resetDir] is true and the overall directionality or the exit
    * directionality of [text] is opposite to the context directionality,
    * a trailing unicode BiDi mark matching the context directionality is
    * appended (LRM or RLM). If [isHtml] is false, we HTML-escape the [text].
    */
   String wrapWithSpan(String text, {bool isHtml: false, bool resetDir: true,
                       TextDirection direction}) {
     if (direction == null) direction = estimateDirection(text, isHtml: isHtml);
     var result;
-    if (!isHtml) text = htmlEscape(text);
+    if (!isHtml) text = HTML_ESCAPE.convert(text);
     var directionChange = contextDirection.isDirectionChange(direction);
     if (_alwaysSpan || directionChange) {
       var spanDirection = '';
       if (directionChange) {
         spanDirection = ' dir=${direction.spanText}';
       }
       result= '<span$spanDirection>$text</span>';
     } else {
       result = text;
     }
@@ skipping 60 matching lines @@
       if (contextDirection == TextDirection.LTR) {
         return Bidi.LRM;
       } else {
         return Bidi.RLM;
       }
     } else {
       return '';
     }
   }
 }