Add Event delegation to Elements and groups of elements.

tools/dom/scripts/htmleventgenerator.py

 #!/usr/bin/python
 # 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.
 
 """This module provides functionality to generate dart:html event classes."""
 
 import logging
 import monitored
 
@@ skipping 274 matching lines @@
       # If the provider is declared elsewhere, point to that.
       redirection = self._GetEventRedirection(interface, html_name, event_type)
       if redirection:
         provider = '%s.%sEvent' % (redirection, html_name)
       else:
         provider = html_name + 'Event'
 
       annotations = self._metadata.GetFormattedMetadata(
           library_name, interface, annotation_name, '  ')
 
+      isElement = False
+      for parent in self._database.Hierarchy(interface):
+        if parent.id == 'Element':
+          isElement = True
       members_emitter.Emit(
           "\n"
-          "  $(ANNOTATIONS)Stream<$TYPE> get $(NAME) => "
-          "$PROVIDER.forTarget(this);\n",
+          "  $(ANNOTATIONS)$(ELEM_TYPE)Stream<$TYPE> get $(NAME) => "
+          "$PROVIDER.for$(ELEM_TYPE)Target(this);\n",
           ANNOTATIONS=annotations,
+          ELEM_TYPE='Element' if isElement else '',
           NAME=getter_name,
           PROVIDER=provider,
           TYPE=event_type)
 
   def _GetRawEvents(self, interface):
     all_interfaces = ([ interface ] +
                       self._database.TransitiveSecondaryParents(interface))
     events = set([])
     for super_interface in all_interfaces:
       events = events.union(
@@ skipping 72 matching lines @@
     """
     key = '%s.%s' % (html_interface_name, dom_event_name)
     if key in _html_event_types:
       return _html_event_types[key]
     key = '*.%s' % dom_event_name
     if key in _html_event_types:
       return _html_event_types[key]
     _logger.warn('Cannot resolve event type for %s.%s' %
         (html_interface_name, dom_event_name))
     return None