Convert EAttachmentHandler to an EExtension.

EAttachmentHandler predates EExtension, so this is really just a code
cleanup to use the extension framework.  But this also demonstrates that
extensions can target interfaces as well as instantiable types, since
EAttachmentView is an interface.

What's also nice is EAttachmentView no longer has to directly interact
with attachment handlers.  Instead of EAttachmentView having to query
each attachment handler for drag-and-drop info, each handler now pushes
its own drag-and-drop info to its EAttachmentView during initialization.

1 files changed, 3 insertions, 2 deletions

diff --git a/widgets/misc/e-attachment-handler.h b/widgets/misc/e-attachment-handler.h
index e7e52c8c18..e85cd9b2ee 100644
--- a/widgets/misc/e-attachment-handler.h
+++ b/widgets/misc/e-attachment-handler.h
@@ -22,6 +22,7 @@
 #ifndef E_ATTACHMENT_HANDLER_H
 #define E_ATTACHMENT_HANDLER_H
 
+#include <e-util/e-extension.h>
 #include <misc/e-attachment-view.h>
 
 /* Standard GObject macros */
@@ -50,12 +51,12 @@ typedef struct _EAttachmentHandlerClass EAttachmentHandlerClass;
 typedef struct _EAttachmentHandlerPrivate EAttachmentHandlerPrivate;
 
 struct _EAttachmentHandler {
-	GObject parent;
+	EExtension parent;
 	EAttachmentHandlerPrivate *priv;
 };
 
 struct _EAttachmentHandlerClass {
-	GObjectClass parent_class;
+	EExtensionClass parent_class;
 
 	GdkDragAction	(*get_drag_actions)	(EAttachmentHandler *handler);
 	const GtkTargetEntry *