I started implementation here: http://cgit.collabora.co.uk/git/user/xclaesse/empathy.git/log/?h=variants

This is still WIP, it gives the UI to select the theme variants, but the variant is not yet applied on the views.

That branch is not complete, but it is hitting a webkit issue I've reported: https://bugs.webkit.org/show_bug.cgi?id=60155

It has the effect that changing variant on-the-fly for a view breaks completely its style.

(In reply to comment #2)
> That branch is not complete

I keep doing that error: s/not/now/ !

FWIW, you can work around that bug by not using document fragments:

function setStylesheet( id, url ) {
    var head = document.getElementsByTagName( "head" ).item(0);

    var newStyle = document.createElement('style');
    newStyle.setAttribute('id', id);
    newStyle.setAttribute('type', 'text/css');
    newStyle.setAttribute('media', 'screen,print');

    if (url.length) 
        newStyle.innerHTML = '@import url("' + url + '");';

    head.removeChild( document.getElementById( id ) );
    head.appendChild( newStyle );
}

That workaround indeed fix the issue. However the JS function is shipped by each Theme, so that would require empathy to patch the html file before loading it... Not sure that's a good idea...

Seems to have odd indentation:

+ /* Create the model */
+ store = gtk_list_store_new (COL_VARIANT_COUNT,
+                             G_TYPE_STRING, /* name */
+                             G_TYPE_BOOLEAN); /* is default */
+ gtk_tree_sortable_set_sort_column_id (GTK_TREE_SORTABLE (store),
+         COL_VARIANT_NAME, GTK_SORT_ASCENDING);

The branch is pretty hard to review, but on a first look it seems okay.

What odd with the indentation? make sure to display tab as 8 spaces, that's the old gossip style.

Webkit 1.4.1 released with the needed fix. Ok to merge this?

Created attachment 189318 [details] [review]
diff

Created attachment 189319 [details] [review]
proper diff

Review of attachment 189319 [details] [review]:

I didn't test the branch yet.

::: libempathy-gtk/empathy-theme-adium.c
@@ +1688,3 @@
+
+	g_free (priv->variant);
+	gchar *script;

g_object_notify() ?

::: libempathy-gtk/empathy-theme-manager.c
@@ +60,3 @@
+	EmpathyAdiumData *adium_data;
+	gchar *adium_variant;
+	GList *adium_views;

Describe the content of the list.

@@ +578,3 @@
+	g_free (priv->adium_variant);
+	if (priv->adium_data != NULL) {
+				     &priv->adium_views);

tp_clear_pointer

::: src/empathy-preferences.c
@@ +884,3 @@
+	g_signal_connect (combo, "changed",
+			  G_CALLBACK (preferences_theme_variant_changed_cb),
+			gtk_combo_box_set_active_iter (combo, &default_iter);

Did you consider using g_settings_bind_with_mapping() ?

@@ +930,3 @@
 		g_free (path);
+		if (info != NULL) {
+			g_hash_table_unref (info);

You can use tp_clear_pointer()

(In reply to comment #11)
> ::: src/empathy-preferences.c
> @@ +884,3 @@
> +    g_signal_connect (combo, "changed",
> +              G_CALLBACK (preferences_theme_variant_changed_cb),
> +            gtk_combo_box_set_active_iter (combo, &default_iter);
> 
> Did you consider using g_settings_bind_with_mapping() ?

Can it work with a combobox to bind the value of the row selected? It is not used in the rest of the code, so I didn't care, tbh.

Fixed the rest.

Branch merged. Note that webkit 1.4.1 is required for variant to be updated correctly, otherwise you'll have to close and reopen chats.