Allow function as replacement argument to String.replaceAll.

sdk/lib/core/regexp.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.
 
 /**
  * [Match] contains methods to manipulate a regular expression match.
  *
  * Iterables of [Match] objects are returned from [RegExp] matching methods.
  *
  * The following example finds all matches of a [RegExp] in a [String]
@@ skipping 42 matching lines @@
    * Returns the number of groups in the regular expression.
    */
   int get groupCount;
 
   /**
    * The string on which this matcher was computed.
    */
   String get str;
 
   /**
-   * The pattern to search for in [str].
+   * The pattern used to search in [str].
    */
   Pattern get pattern;
 }
 
 
 /**
  * [RegExp] represents regular expressions.
  *
  * Dart regular expressions have the same syntax and semantics as
  * JavaScript regular expressions. See
@@ skipping 53 matching lines @@
   /**
    * Whether this regular expression matches multiple lines.
    */
   bool get multiLine;
 
   /**
    * Whether this regular expression is case insensitive.
    */
   bool get ignoreCase;
 }