[mutter] gschema: Turn experimental features into flags

[Marge Bot <marge-bot src gnome org>]

commit 331f08fc40039ba3eb9dbe51d98d22183a842de1
Author: Robert Mader <robert mader posteo de>
Date:   Mon Aug 9 12:07:14 2021 +0200

    gschema: Turn experimental features into flags
    
    Defining valid values makes
    1. changing settings less error prone
    2. sure they are discoverable.
    
    This does reset the values once on update, but fortunately does *not*
    change the way to set the values. Thus e.g. enabling fractional scaling
    via terminal command still works as before and internet guides stay valid.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1961>

 data/org.gnome.mutter.gschema.xml.in | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
---
diff --git a/data/org.gnome.mutter.gschema.xml.in b/data/org.gnome.mutter.gschema.xml.in
index 0ebdf9257a..467d775636 100644
--- a/data/org.gnome.mutter.gschema.xml.in
+++ b/data/org.gnome.mutter.gschema.xml.in
@@ -1,4 +1,13 @@
 <schemalist>
+
+  <flags id="org.gnome.mutter.MetaExperimentalFeature">
+    <value nick="scale-monitor-framebuffer" value="1"/>
+    <value nick="kms-modifiers" value="2"/>
+    <value nick="rt-scheduler" value="4"/>
+    <value nick="dma-buf-screen-sharing" value="8"/>
+    <value nick="autoclose-xwayland" value="16"/>
+  </flags>
+
   <schema id="org.gnome.mutter" path="/org/gnome/mutter/"
           gettext-domain="@GETTEXT_DOMAIN@">
 
@@ -102,7 +111,8 @@
       </description>
     </key>
 
-    <key name="experimental-features" type="as">
+    <key name="experimental-features"
+        flags='org.gnome.mutter.MetaExperimentalFeature'>
       <default>[]</default>
       <summary>Enable experimental features</summary>
       <description>