[gtk] Theme: add helper class names for Adwaita

[Timm Bäder <baedert src gnome org>]

commit 756e8f3189eb9993a54baa7cf778e62d9087b451
Author: Jakub Steiner <jimmac gmail com>
Date:   Mon Dec 10 14:16:52 2018 +0100

    Theme: add helper class names for Adwaita
    
    - helps legibility of app icons
    
    Addresses https://gitlab.gnome.org/GNOME/gtk/issues/1434

 gtk/ui/gtkaboutdialog.ui      | 3 +++
 gtk/ui/gtkappchooserwidget.ui | 7 ++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/gtk/ui/gtkaboutdialog.ui b/gtk/ui/gtkaboutdialog.ui
index 4d96454521..3d4996fa45 100644
--- a/gtk/ui/gtkaboutdialog.ui
+++ b/gtk/ui/gtkaboutdialog.ui
@@ -27,6 +27,9 @@
             <child>
               <object class="GtkImage" id="logo_image">
                 <property name="icon-name">image-missing</property>
+                <style>
+                  <class name="icon-dropshadow"/>
+                </style>
               </object>
             </child>
             <child>
diff --git a/gtk/ui/gtkappchooserwidget.ui b/gtk/ui/gtkappchooserwidget.ui
index d23a402ca8..484599d16a 100644
--- a/gtk/ui/gtkappchooserwidget.ui
+++ b/gtk/ui/gtkappchooserwidget.ui
@@ -58,7 +58,12 @@
                       <object class="GtkCellRendererText" id="secondary_padding"/>
                     </child>
                     <child>
-                      <object class="GtkCellRendererPixbuf" id="app_icon"/>
+                      <object class="GtkCellRendererPixbuf" id="app_icon">
+                        <style>
+                          <class name="lowres-icon"/>
+                        </style>
+                        <property name="stock-size">5</property>
+                      </object>
                       <attributes>
                         <attribute name="gicon">1</attribute>
                       </attributes>