[fractal] media_viewer: Make OSD buttons circular

[Daniel Garcia Moreno <danigm src gnome org>]

commit f615362d6e3cd898e90c001b917f56df34d47c17
Author: Christopher Davis <brainblasted disroot org>
Date:   Fri Oct 2 17:35:35 2020 -0700

    media_viewer: Make OSD buttons circular
    
    Newer mockups for image viewers have circular
    navigation buttons.

 fractal-gtk/res/ui/media_viewer.ui | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/fractal-gtk/res/ui/media_viewer.ui b/fractal-gtk/res/ui/media_viewer.ui
index df16f4ef..ba80ae21 100644
--- a/fractal-gtk/res/ui/media_viewer.ui
+++ b/fractal-gtk/res/ui/media_viewer.ui
@@ -148,6 +148,7 @@
                         </child>
                         <style>
                           <class name="osd"/>
+                          <class name="round-button"/>
                         </style>
                       </object>
                     </child>
@@ -194,6 +195,7 @@
                         </child>
                         <style>
                           <class name="osd"/>
+                          <class name="round-button"/>
                         </style>
                       </object>
                     </child>