Relax feature defines restrictions.

tools/dom/scripts/databasebuilder.py

 #!/usr/bin/python
 # 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.
 
 import copy
 import database
 import idlparser
 import logging
 import multiprocessing
@@ skipping 388 matching lines @@
         if target_name:
           # [Supplemental=DOMWindow] - merge into DOMWindow.
           target = target_name
         else:
           # [Supplemental] - merge into existing inteface with same name.
           target = interface.id
         if self._database.HasInterface(target):
           old_interface = self._database.GetInterface(target)
           self._merge_interfaces(old_interface, interface, import_options)
         else:
-          raise Exception("Supplemental target '%s' not found", target)
+          _logger.warning("Supplemental target '%s' not found", target)
 
     # Step 4: Resolve 'implements' statements
     for impl_stmt, import_options in self._impl_stmts:
       self._merge_impl_stmt(impl_stmt, import_options)
 
     self._impl_stmts = []
     self._imported_interfaces = []
 
   def import_idl_files(self, file_paths, import_options, parallel):
     if parallel:
@@ skipping 147 matching lines @@
       # TODO(antonm): Ideally we'd like to have pristine copy of WebKit IDLs and fetch
       # this information directly from it.  Unfortunately right now database is massaged
       # a lot so it's difficult to maintain necessary information on DOMWindow itself.
       interface = self._database.GetInterface(type)
       if 'V8EnabledPerContext' in attr.ext_attrs:
         interface.ext_attrs['synthesizedV8EnabledPerContext'] = \
             attr.ext_attrs['V8EnabledPerContext']
       if 'V8EnabledAtRuntime' in attr.ext_attrs:
         interface.ext_attrs['synthesizedV8EnabledAtRuntime'] = \
             attr.ext_attrs['V8EnabledAtRuntime'] or attr.id