[gtk+] headerbar: don't allocate both label and custom title

[Ray Strode <halfline src gnome org>]

commit 01eda209e19f02b507a8ddd73ae3b2bf74e7d5c2
Author: Ray Strode <rstrode redhat com>
Date:   Thu Jun 23 08:57:55 2016 -0400

    headerbar: don't allocate both label and custom title
    
    It's only possible to have a label or a custom title, not both.
    The size allocate code confusingly treats them as independent.
    
    That is confusing, because, as the code is written, it makes it
    look like the space for the custom title isn't getting accounted
    for.
    
    This commit else-ifies some parts of the size allocate code for
    clarity.

 gtk/gtkheaderbar.c |    6 ++----
 1 files changed, 2 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtkheaderbar.c b/gtk/gtkheaderbar.c
index 5c5b13a..b133587 100644
--- a/gtk/gtkheaderbar.c
+++ b/gtk/gtkheaderbar.c
@@ -1042,8 +1042,7 @@ gtk_header_bar_allocate_contents (GtkCssGadget        *gadget,
                                                  &title_minimum_size,
                                                  &title_natural_size);
     }
-
-  if (priv->label_box != NULL)
+  else if (priv->label_box != NULL)
     {
       gtk_widget_get_preferred_width_for_height (priv->label_box,
                                                  height,
@@ -1157,8 +1156,7 @@ gtk_header_bar_allocate_contents (GtkCssGadget        *gadget,
   if (priv->custom_title != NULL &&
       gtk_widget_get_visible (priv->custom_title))
     gtk_widget_size_allocate (priv->custom_title, &child_allocation);
-
-  if (priv->label_box != NULL)
+  else if (priv->label_box != NULL)
     gtk_widget_size_allocate (priv->label_box, &child_allocation);
 
   child_allocation.y = allocation->y;