erp5_base: use Event_createPostMessage instead of duplicated code

bt5/erp5_base/SkinTemplateItem/portal_skins/erp5_base/Entity_sendEmail.py

@@ -29,18 +29,8 @@ mail_message = portal.Base_createMailMessageAsString(
   embedded_file_list=embedded_file_list,
   extra_header_dict=extra_header_dict)
 
-internet_message_post_module = portal.getDefaultModuleValue('Internet Message Post', None)
-if internet_message_post_module is not None:
-  # erp5_interface_post is installed, so it is needed to track outgoing emails
-  internet_message_post = internet_message_post_module.newContent(
-    portal_type='Internet Message Post',
-    title="Internet Message for %s" % event.getTitle(),
-    reference=event.getReference(),
-    data=mail_message,
-  )
-  internet_message_post.allowExport()
-  event_aggregate_list = event.getAggregateList()
-  event_aggregate_list.append(internet_message_post.getRelativeUrl())
-  event.setAggregateList(event_aggregate_list)
+create_post_message_method = getattr(event, 'Event_createPostMessage', None)
+if create_post_message_method:
+  create_post_message_method(mail_message)
 else:
   event.sendMailHostMessage(mail_message)

bt5/erp5_base/SkinTemplateItem/portal_skins/erp5_base/MailMessage_send.py

@@ -47,6 +47,9 @@ if not context.hasStartDate():
   context.setStartDate(DateTime())
 
 if download or not use_activity:
+
+  create_post_message_method = getattr(context, 'Event_createPostMessage', None)
+
   for to_url in to_url_list:
     body = body or context.getTextContent() or ''
     subject = subject or context.getTitle() or ''
@@ -79,20 +82,8 @@ if download or not use_activity:
       embedded_file_list=embedded_file_list,
       extra_header_dict=extra_header_dict)
 
-    internet_message_post_module = portal.getDefaultModuleValue('Internet Message Post', None)
-    if internet_message_post_module is not None:
-      # erp5_interface_post is installed, so it is needed to track outgoing emails
-      internet_message_post = internet_message_post_module.newContent(
-        portal_type='Internet Message Post',
-        title="Internet Message for %s" % context.getTitle(),
-        reference=context.getReference(),
-        data=mail_message,
-      )
-      internet_message_post.allowExport()
-
-      mail_aggregate_list = context.getAggregateList()
-      mail_aggregate_list.append(internet_message_post.getRelativeUrl())
-      context.setAggregateList(mail_aggregate_list)
+    if create_post_message_method:
+      create_post_message_method(mail_message)
     else:
       if not use_activity:
         context.activate(activity='SQLQueue').sendMailHostMessage(mail_message)