Change IllegalArgumentException to ArgumentError.

runtime/lib/string_base.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.
 
 /**
  * [StringBase] contains common methods used by concrete String implementations,
  * e.g., OneByteString.
  */
 class StringBase {
 
@@ skipping 176 matching lines @@
 
   bool contains(Pattern pattern, [int startIndex = 0]) {
     if (pattern is String) {
       return indexOf(pattern, startIndex) >= 0;
     }
     return pattern.allMatches(this.substring(startIndex)).iterator().hasNext();
   }
 
   String replaceFirst(Pattern pattern, String replacement) {
     if (pattern is! Pattern) {
-      throw new IllegalArgumentException("${pattern} is not a Pattern");
+      throw new ArgumentError("${pattern} is not a Pattern");
     }
     if (replacement is! String) {
-      throw new IllegalArgumentException("${replacement} is not a String");
+      throw new ArgumentError("${replacement} is not a String");
     }
     StringBuffer buffer = new StringBuffer();
     int startIndex = 0;
     Iterator iterator = pattern.allMatches(this).iterator();
     if (iterator.hasNext()) {
       Match match = iterator.next();
       buffer.add(this.substring(startIndex, match.start())).add(replacement);
       startIndex = match.end();
     }
     return buffer.add(this.substring(startIndex)).toString();
   }
 
   String replaceAll(Pattern pattern, String replacement) {
     if (pattern is! Pattern) {
-      throw new IllegalArgumentException("${pattern} is not a Pattern");
+      throw new ArgumentError("${pattern} is not a Pattern");
     }
     if (replacement is! String) {
-      throw new IllegalArgumentException("${replacement} is not a String");
+      throw new ArgumentError("${replacement} is not a String");
     }
     StringBuffer buffer = new StringBuffer();
     int startIndex = 0;
     for (Match match in pattern.allMatches(this)) {
       buffer.add(this.substring(startIndex, match.start())).add(replacement);
       startIndex = match.end();
     }
     return buffer.add(this.substring(startIndex)).toString();
   }
 
@@ skipping 250 matching lines @@
     for (int g in groups) {
       result.add(group(g));
     }
     return result;
   }
 
   final int _start;
   final String str;
   final String pattern;
 }