[gtk+] widget: Call size_allocate vfunc directly when possible

[Alexander Larsson <alexl src gnome org>]

commit 68e50d20a7f765b3b5c6196f0d4de134fc111bac
Author: Alexander Larsson <alexl redhat com>
Date:   Mon Sep 14 15:05:37 2015 +0200

    widget: Call size_allocate vfunc directly when possible
    
    This avoids all the overhead of signal emissions when it is not used.

 gtk/gtkwidget.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 4206c40..7a05785 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -5969,7 +5969,10 @@ gtk_widget_size_allocate_with_baseline (GtkWidget     *widget,
     goto out;
 
   priv->allocated_baseline = baseline;
-  g_signal_emit (widget, widget_signals[SIZE_ALLOCATE], 0, &real_allocation);
+  if (g_signal_has_handler_pending (widget, widget_signals[SIZE_ALLOCATE], 0, FALSE))
+    g_signal_emit (widget, widget_signals[SIZE_ALLOCATE], 0, &real_allocation);
+  else
+    GTK_WIDGET_GET_CLASS (widget)->size_allocate (widget, &real_allocation);
 
   /* Size allocation is god... after consulting god, no further requests or allocations are needed */
   priv->alloc_needed = FALSE;