Fix another csslib IE10 test failure.

pkg/csslib/test/declaration_test.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.
 
 library declaration_test;
 
 import 'package:unittest/unittest.dart';
 import 'testing.dart';
 
 
@@ skipping 994 matching lines @@
 
   expect(stylesheet != null, true);
 
   expect(errors.length, 1, reason: errors.toString());
 
   errorMessage = errors[0];
   expect(errorMessage.message, contains('unexpected end of file'));
   expect(errorMessage.span, isNotNull);
   expect(errorMessage.span.start.line, 7);
   expect(errorMessage.span.start.column, 0);
-  expect(errorMessage.span.text, '');
+  expect(errorMessage.span.text.trim(), '');
 }
 
 main() {
   test('Simple Terms', testSimpleTerms);
   test('Declarations', testDeclarations);
   test('Identifiers', testIdentifiers);
   test('Composites', testComposites);
   test('Units', testUnits);
   test('Unicode', testUnicode);
   test('Newer CSS', testNewerCss);
   test('Media Queries', testMediaQueries);
   test('Font-Face', testFontFace);
   test('CSS file', testCssFile);
   test('Compact Emitter', testCompactEmitter);
   test('Selector Negation', testNotSelectors);
   test('IE stuff', testIE);
   test('IE declaration syntax', testIEDeclaration);
   test('Hanging bugs', testHangs);
 }