Get rid of ===/!===.

lib/html/scripts/css_code_generator.py

 #!/usr/bin/python2.6
 #
 # Copyright (c) 2011, 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 from css property definitions defined in WebKit."""
 
 import tempfile, os
 
@@ skipping 91 matching lines @@
 //   %s
 
 // TODO(jacobr): add versions that take numeric values in px, miliseconds, etc.
 
 class CSSStyleDeclarationWrappingImplementation extends DOMWrapperBase implements CSSStyleDeclaration {
   static String _cachedBrowserPrefix;
 
   CSSStyleDeclarationWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
 
   static String get _browserPrefix {
-    if (_cachedBrowserPrefix === null) {
+    if (_cachedBrowserPrefix == null) {
       if (_Device.isFirefox) {
         _cachedBrowserPrefix = '-moz-';
       } else {
         _cachedBrowserPrefix = '-webkit-';
       }
       // TODO(jacobr): support IE 9.0 and Opera as well.
     }
     return _cachedBrowserPrefix;
   }
 
@@ skipping 87 matching lines @@
   interface_file.write(''.join(interface_lines));
   interface_file.write('}\n')
   interface_file.close()
 
   class_file.write(''.join(class_lines));
   class_file.write('}\n')
   class_file.close()
 
 if __name__ == '__main__':
   main()