Deprecate Math object in corelib in favor of dart:math library.

utils/css/css.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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('css');
 
+#import('dart:math', prefix: 'Math');
 #import("../lib/file_system.dart");
 #import('../lib/file_system_memory.dart');
 
 #source('cssoptions.dart');
 #source('source.dart');
 #source('tokenkind.dart');
 #source('token.dart');
 #source('tokenizer_base.dart');
 #source('tokenizer.dart');
 #source('treebase.dart');
@@ skipping 45 matching lines @@
       output = prettyTree;
     }
   } catch (var e) {
     String error = e.toString();
     output = "$error\n$prettyTree";
     throw e;
   }
 
   return output;
 }