Moved most of html lib generating scripts into tools.

tools/dom/templates/html/dartium/impl_Window.darttemplate

 // 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 html;
 
 /// @domName $DOMNAME
 class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
 
   /**
@@ skipping 19 matching lines @@
    * port may be retrieved by any isolate (or JavaScript script)
    * running in this window.
    */
   registerPort(String name, var port) {
     var serialized = _serialize(port);
     document.documentElement.attributes['dart-port:$name'] = JSON.stringify(serialized);
   }
 
 $!MEMBERS
 }