Add Event delegation to Elements and groups of elements.

tools/dom/scripts/htmleventgenerator.py

Index: tools/dom/scripts/htmleventgenerator.py
diff --git a/tools/dom/scripts/htmleventgenerator.py b/tools/dom/scripts/htmleventgenerator.py
index 509e717f5acc213f5da7f4b816f91179f1f37bea..eee08c619708b92f88743633887e4167c8accfbc 100644
--- a/tools/dom/scripts/htmleventgenerator.py
+++ b/tools/dom/scripts/htmleventgenerator.py
@@ -272,7 +272,8 @@ class HtmlEventGenerator(object):
           TYPE=event_type)
 
   def EmitStreamGetters(self, interface, custom_events,
-      members_emitter, library_name):
+      members_emitter, library_name, stream_getter_signatures_emitter=None,
+      element_stream_getters_emitter=None):
     events = self._GetEvents(interface, custom_events)
     if not events:
       return
@@ -292,14 +293,33 @@ class HtmlEventGenerator(object):
       annotations = self._metadata.GetFormattedMetadata(
           library_name, interface, annotation_name, '  ')
 
-      members_emitter.Emit(
-          "\n"
-          "  $(ANNOTATIONS)Stream<$TYPE> get $(NAME) => "
-          "$PROVIDER.forTarget(this);\n",
-          ANNOTATIONS=annotations,
-          NAME=getter_name,
-          PROVIDER=provider,
-          TYPE=event_type)
+      isElement = False
+      for parent in self._database.Hierarchy(interface):
+        if parent.id == 'Element':
+          isElement = True
+      # We add the same event stream getters Element, ElementList, and
+      # _FrozenElementList. So, in impl_Element.darttemplate, we have two
+      # additional emitters to add the correct variation of the stream getter
+      # for that context.
+      for emitter in [members_emitter, stream_getter_signatures_emitter,
+          element_stream_getters_emitter]:
+        if emitter == None:
+          continue
+        elem_type = 'Element' if isElement else ''
+        call_name = 'forElement' if isElement else 'forTarget'
+        if emitter == element_stream_getters_emitter:
+          call_name = '_forElementList'
+        emitter.Emit(
+            "\n"
+            "  $(ANNOTATIONS)$(ELEM_TYPE)Stream<$TYPE> get $(NAME)$BODY;\n",
+            ANNOTATIONS=annotations,
+            ELEM_TYPE=elem_type,
+            NAME=getter_name,
+            BODY = ('' if emitter == stream_getter_signatures_emitter else
+                ' => %s.%s(this)' % (((''
+                if emitter != element_stream_getters_emitter else 'Element.')
+                  + provider), call_name)),
+            TYPE=event_type)
 
   def _GetRawEvents(self, interface):
     all_interfaces = ([ interface ] +