colorchooserdialog: Add "colorchooser" style class

gtk/gtkcolorchooserdialog.c

@@ -48,6 +48,11 @@ G_GNUC_BEGIN_IGNORE_DEPRECATIONS
  *
  * `GtkColorChooserDialog` has been deprecated in favor of [class@Gtk.ColorDialog].
  *
+ * ## CSS nodes
+ *
+ * `GtkColorChooserDialog` has a single CSS node with the name `window` and style
+ * class `.colorchooser`.
+ *
  * Deprecated: 4.10: Use [class@Gtk.ColorDialog] instead
  */
 

gtk/ui/gtkcolorchooserdialog.ui

@@ -3,6 +3,9 @@
   <template class="GtkColorChooserDialog" parent="GtkDialog">
     <property name="title" translatable="yes">Select a Color</property>
     <property name="resizable">0</property>
+    <style>
+      <class name="colorchooser"/>
+    </style>
     <child internal-child="content_area">
       <object class="GtkBox" id="dialog-vbox1">
         <property name="orientation">1</property>