Use clutter_actor_destroy in dispose, add _dispose where needed

ClutterGroup calls _destroy, but most of St was just calling _unparent.
This caused problems because the DESTROY signal was not emitted
for child elements after destroying a toplevel.  Also, in a GC'd
binding it would cause unpredictable lifetime of children.

Some St widgets simply didn't have _dispose at all; implement it.

Note because of the usage of the background_image in StButton,
we can't cleanly destroy it inside the StWidget.

https://bugzilla.gnome.org/show_bug.cgi?id=597845

src/st/st-bin.c

@@ -352,10 +352,8 @@ st_bin_dispose (GObject *gobject)
   StBinPrivate *priv = ST_BIN (gobject)->priv;
 
   if (priv->child)
-    {
-      clutter_actor_unparent (priv->child);
-      priv->child = NULL;
-    }
+    clutter_actor_destroy (priv->child);
+  g_assert (priv->child == NULL);
 
   G_OBJECT_CLASS (st_bin_parent_class)->dispose (gobject);
 }

src/st/st-box-layout.c

@@ -403,11 +403,7 @@ st_box_layout_dispose (GObject *object)
   StBoxLayoutPrivate *priv = ST_BOX_LAYOUT (object)->priv;
 
   while (priv->children)
-    {
-      clutter_actor_unparent (CLUTTER_ACTOR (priv->children->data));
-
-      priv->children = g_list_delete_link (priv->children, priv->children);
-    }
+    clutter_actor_destroy (priv->children->data);
 
   if (priv->hadjustment)
     {

src/st/st-entry.c

@@ -162,7 +162,7 @@ st_entry_dispose (GObject *object)
 
   if (priv->entry)
     {
-      clutter_actor_unparent (priv->entry);
+      clutter_actor_destroy (priv->entry);
       priv->entry = NULL;
     }
 }

src/st/st-label.c

@@ -183,6 +183,20 @@ st_label_allocate (ClutterActor          *actor,
   clutter_actor_allocate (priv->label, &content_box, flags);
 }
 
+static void
+st_label_dispose (GObject   *actor)
+{
+  StLabelPrivate *priv = ST_LABEL (actor)->priv;
+
+  if (priv->label)
+    {
+      clutter_actor_destroy (priv->label);
+      priv->label = NULL;
+    }
+
+  G_OBJECT_CLASS (st_label_parent_class)->dispose (G_OBJECT (actor));
+}
+
 static void
 st_label_paint (ClutterActor *actor)
 {
@@ -227,6 +241,7 @@ st_label_class_init (StLabelClass *klass)
 
   gobject_class->set_property = st_label_set_property;
   gobject_class->get_property = st_label_get_property;
+  gobject_class->dispose = st_label_dispose;
 
   actor_class->paint = st_label_paint;
   actor_class->allocate = st_label_allocate;

src/st/st-scroll-view.c

@@ -129,13 +129,13 @@ st_scroll_view_dispose (GObject *object)
 
   if (priv->vscroll)
     {
-      clutter_actor_unparent (priv->vscroll);
+      clutter_actor_destroy (priv->vscroll);
       priv->vscroll = NULL;
     }
 
   if (priv->hscroll)
     {
-      clutter_actor_unparent (priv->hscroll);
+      clutter_actor_destroy (priv->hscroll);
       priv->hscroll = NULL;
     }
 

src/st/st-table.c

@@ -271,15 +271,9 @@ static void
 st_table_dispose (GObject *gobject)
 {
   StTablePrivate *priv = ST_TABLE (gobject)->priv;
-  GSList *l, *next;
 
-  for (l = priv->children; l;)
-    {
-      next = l->next;
-      clutter_container_remove_actor ((ClutterContainer *) gobject,
-                                      CLUTTER_ACTOR (l->data));
-      l = next;
-    }
+  while (priv->children)
+    clutter_actor_destroy (priv->children->data);
 
   G_OBJECT_CLASS (st_table_parent_class)->dispose (gobject);
 }

src/st/st-tooltip.c

@@ -355,6 +355,20 @@ st_tooltip_unmap (ClutterActor *self)
   clutter_actor_unmap (priv->label);
 }
 
+static void
+st_tooltip_dispose (GObject *self)
+{
+  StTooltipPrivate *priv = ST_TOOLTIP (self)->priv;
+
+  if (priv->label)
+    {
+      clutter_actor_destroy (priv->label);
+      priv->label = NULL;
+    }
+
+  G_OBJECT_CLASS (st_tooltip_parent_class)->dispose (self);
+}
+
 static void
 st_tooltip_class_init (StTooltipClass *klass)
 {
@@ -367,6 +381,7 @@ st_tooltip_class_init (StTooltipClass *klass)
 
   gobject_class->set_property = st_tooltip_set_property;
   gobject_class->get_property = st_tooltip_get_property;
+  gobject_class->dispose = st_tooltip_dispose;
 
   actor_class->get_preferred_width = st_tooltip_get_preferred_width;
   actor_class->get_preferred_height = st_tooltip_get_preferred_height;