Created attachment 268534 [details] [review]
Rename GtkActionBar to GtkCenterBox

Created attachment 268535 [details] [review]
Add new ActionBar

Created attachment 268536 [details] [review]
tests: add a visibility toggle to the action bar test

Review of attachment 268535 [details] [review]:

::: gtk/gtkcenterbox.c
@@ -37,3 @@
  * @See_also: #GtkBox
  *
- * GtkCenterBox is similar to a horizontal #GtkBox, it allows to place

This should go into the first commit

Running testactionbar, I get

(lt-testactionbar:12741): Gtk-WARNING **: GtkButton 0x1b6c350 is mapped but visible=1 child_visible=1 parent GtkCenterBox 0x1b42250 mapped=0

Created attachment 268843 [details] [review]
Rename GtkActionBar to GtkCenterBox

Created attachment 268844 [details] [review]
Add new ActionBar

Created attachment 268845 [details] [review]
tests: add a visibility toggle to the action bar test

Review of attachment 268843 [details] [review]:

I still hope that we can drop this and add the center widget to GtkBox, but for now this is ok. It is certainly a better name for this generic container

Review of attachment 268844 [details] [review]:

::: gtk/gtkactionbar.c
@@ +41,3 @@
+ *
+ * It allows placing children at the start or the end. In addition, it
+ * contains an internal centered box which is centered with respect to

It is not really a box, and not really internal either (after all, you;re setting it with set_center_widget).

@@ +48,3 @@
+struct _GtkActionBarPrivate
+{
+  GtkWidget *center_box;

should rename this to center_widget, to match the setter, and the fact that it is not a box.

@@ +157,3 @@
+                                      pspec->name,
+                                      value);
+}

Not that it is very likely to occur in practice, but I think you need to just return the default value here, for the revealer. Compare gtkheaderbar

Review of attachment 268845 [details] [review]:

sure

Attachment 268843 [details] pushed as c86ee05 - Rename GtkActionBar to GtkCenterBox
Attachment 268844 [details] pushed as d0a654e - Add new ActionBar
Attachment 268845 [details] pushed as 70a2772 - tests: add a visibility toggle to the action bar test