Fix csslib test failures on IE10.

pkg/csslib/lib/src/token.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 csslib.parser;
 
 /**
  * A single token in the Dart language.
  */
 class Token {
@@ skipping 10 matching lines @@
   int get end => span.end.offset;
 
   /** Returns the source text corresponding to this [Token]. */
   String get text => span.text;
 
   Token(this.kind, this.span);
 
   /** Returns a pretty representation of this token for error messages. **/
   String toString() {
     var kindText = TokenKind.kindToString(kind);
-    var actualText = text;
+    var actualText = text.trim();
     if (kindText != actualText) {
       if (actualText.length > 10) {
         actualText = '${actualText.substring(0, 8)}...';
       }
       return '$kindText($actualText)';
     } else {
       return kindText;
     }
   }
 }
@@ skipping 15 matching lines @@
  *
  * See <http://dev.w3.org/csswg/css-syntax/#typedef-ident-token> and
  * <http://dev.w3.org/csswg/css-syntax/#ident-token-diagram>.
  */
 class IdentifierToken extends Token {
   final String text;
 
   IdentifierToken(this.text, int kind, SourceSpan span)
       : super(kind, span);
 }