Remove JS_CONST from CssStyleDeclaration, causes DDC problems

tools/dom/scripts/css_code_generator.py

 #!/usr/bin/python
 #
 # Copyright (c) 2014, 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.
 
 """Generates CSSStyleDeclaration template file from css property definitions
 defined in WebKit."""
 
 import tempfile, os, re
@@ skipping 177 matching lines @@
   }
 $else
   static String _readCache(String key) => null;
   static void _writeCache(String key, value) {}
 $endif
 
   static String _camelCase(String hyphenated) {
 $if DART2JS
     var replacedMs = JS('String', r'#.replace(/^-ms-/, "ms-")', hyphenated);
 
-    var fToUpper = const JS_CONST(
+    var fToUpper = JS('',
         r'function(_, letter) { return letter.toUpperCase(); }');
     return JS('String', r'#.replace(/-([\da-z])/ig, #)', replacedMs, fToUpper);
 $else
     // The "ms" prefix is always lowercased.
     return hyphenated.replaceFirst(new RegExp('^-ms-'), 'ms-').replaceAllMapped(
         new RegExp('-([a-z]+)', caseSensitive: false),
         (match) => match[0][1].toUpperCase() + match[0].substring(2));
 $endif
   }
 
@@ skipping 146 matching lines @@
       class_lines.append(annotated[base_css_name])
     class_lines.append("""
   set %s(String value) {
     setProperty('%s', value, '');
   }
 """ % (camel_case_name, css_name))
 
   class_file.write(''.join(class_lines));
   class_file.write('}\n')
   class_file.close()