Refactor the event-generation code to locate it in systemhtml.py.

client/dom/scripts/systemwrapping.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 systems to generate
 wrapping binding from the IDL database."""
 
 import os
 from generator import *
@@ skipping 172 matching lines @@
         NAME=attr.id, TYPE=DartType(attr.type.id), METHOD=method_name)
 
   def AddSecondaryAttribute(self, interface, getter, setter):
     self._SecondaryContext(interface)
     self.AddAttribute(getter, setter)
 
   def AddSecondaryOperation(self, interface, info):
     self._SecondaryContext(interface)
     self.AddOperation(info)
 
-  def AddEventAttributes(self, event_attrs):
-    pass
-
   def _SecondaryContext(self, interface):
     if interface is not self._current_secondary_parent:
       self._current_secondary_parent = interface
       self._members_emitter.Emit('\n  // From $WHERE\n', WHERE=interface.id)
 
   def AddIndexer(self, element_type):
     """Adds all the methods required to complete implementation of List."""
     # We would like to simply inherit the implementation of everything except
     # get length(), [], and maybe []=.  It is possible to extend from a base
     # array implementation class only when there is no other implementation
@@ skipping 327 matching lines @@
     # dispatch has removed f(X), leaving only f(Y), but there is no guarantee
     # that Y = Z-X, so we need to check for Y.
     true_code = emitter.Emit(
         '$(INDENT)if ($COND) {\n'
         '$!TRUE'
         '$(INDENT)}\n',
         COND=test, INDENT=indent)
     self.GenerateDispatch(
         true_code, info, indent + '  ', position + 1, positive)
     return True