Fixing up WheelEvent to follow W3C standards and work on all platforms.

lib/html/scripts/systemhtml.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 shared functionality for the system to generate
 Dart:html APIs from the IDL database."""
 
 import emitter
 
 from systemdart2js import *
 from systeminterface import *
 
 _js_custom_members = set([
     'CSSStyleDeclaration.setProperty',
     'Element.insertAdjacentElement',
     'Element.insertAdjacentHTML',
     'Element.insertAdjacentText',
+    'ElementEvents.mouseWheel',
     'IDBDatabase.transaction',
     'IFrameElement.contentWindow',
     'MouseEvent.offsetX',
     'MouseEvent.offsetY',
     'TableElement.createTBody',
     'Window.document',
     'Window.top',
     'Window.location',
     'Window.open',
     ])
@@ skipping 674 matching lines @@
       return
 
     self._EmitEventGetter(events_interface, events_class)
 
     events_members = self._interface_emitter.Emit(
         '\nabstract class $INTERFACE implements $PARENTS {\n$!MEMBERS}\n',
         INTERFACE=events_interface,
         PARENTS=', '.join(
             self._shared.GetParentsEventsClasses(self._interface)))
 
-    # TODO(jacobr): specify the type of _ptr as EventTarget
-    implementation_events_members = self._implementation_emitter.Emit(
+    template_file = 'impl_%s.darttemplate' % events_interface
+    template = (self._backend._system._templates.TryLoad(template_file) or
         '\n'
         'class $CLASSNAME extends $SUPER implements $INTERFACE {\n'
         '  $CLASSNAME(_ptr) : super(_ptr);\n'
-        '$!MEMBERS}\n',
+        '$!MEMBERS}\n')
+
+    # TODO(jacobr): specify the type of _ptr as EventTarget
+    implementation_events_members = self._implementation_emitter.Emit(
+        template,
         CLASSNAME=events_class,
         INTERFACE=events_interface,
         SUPER=parent_events_class)
 
     event_attrs = DomToHtmlEvents(self._html_interface_name, event_attrs)
     for event_name in event_attrs:
       if event_name in _html_event_names:
+        dart_event_name = _html_event_names[event_name]
         events_members.Emit('\n  EventListenerList get $NAME;\n',
-          NAME=_html_event_names[event_name])
-        implementation_events_members.Emit(
-            "\n"
-            "  EventListenerList get $NAME => this['$DOM_NAME'];\n",
-            NAME=_html_event_names[event_name],
-            DOM_NAME=event_name)
+          NAME=dart_event_name)
+        if not self._backend.HasCustomEventImplementation(dart_event_name):
+          implementation_events_members.Emit(
+              "\n"
+              "  EventListenerList get $NAME => this['$DOM_NAME'];\n",
+              NAME=dart_event_name,
+              DOM_NAME=event_name)
       else:
         raise Exception('No known html even name for event: ' + event_name)
 
   def _EmitEventGetter(self, events_interface, events_class):
     self._members_emitter.Emit(
         '\n  /**'
         '\n   * @domName EventTarget.addEventListener, '
         'EventTarget.removeEventListener, EventTarget.dispatchEvent'
         '\n   */'
         '\n  $TYPE get on;\n',
@@ skipping 460 matching lines @@
   def _OutputConversion(self, idl_type, member):
     return FindConversion(idl_type, 'get', self._interface.id, member)
 
   def _InputConversion(self, idl_type, member):
     return FindConversion(idl_type, 'set', self._interface.id, member)
 
   def _HasCustomImplementation(self, member_name):
     member_name = '%s.%s' % (self._html_interface_name, member_name)
     return member_name in _js_custom_members
 
+  def HasCustomEventImplementation(self, member_name):
+    member_name = '%sEvents.%s' % (self._html_interface_name, member_name)
+    return member_name in _js_custom_members
+
   def _HasJavaScriptIndexingBehaviour(self):
     """Returns True if the native object has an indexer and length property."""
     (element_type, requires_indexer) = ListImplementationInfo(
         self._interface, self._database)
     if element_type and requires_indexer: return True
     return False
 
 # ------------------------------------------------------------------------------
 
 class HtmlDart2JSSystem(System):
 
   def __init__(self, options):
     super(HtmlDart2JSSystem, self).__init__(options)
 
   def ImplementationGenerator(self, interface):
     return HtmlDart2JSClassGenerator(self, interface)
 
   def GenerateLibraries(self, dart_files):
     auxiliary_dir = os.path.relpath(self._auxiliary_dir, self._output_dir)
     self._GenerateLibFile(
         'html_dart2js.darttemplate',
         os.path.join(self._output_dir, 'html_dart2js.dart'),
         dart_files,
         AUXILIARY_DIR=systembase.MassagePath(auxiliary_dir))
 
   def Finish(self):
     pass