Show: Show Media Controls hides the playback bar

The Slide Show checkbox wrote nothing. show.setup now stores
showMediaControls, and the show draws the playback bar and GIF button
only while that setting is on.

crates/engine/src/cmd/review.rs

@@ -27,7 +27,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Set Up Slide Show…",
             ["Slide Show", "Set Up"],
             None,
-            "{type?: speaker|browsed|kiosk, loop?: bool, noNarration?, noAnimation?, useTimings?, from?, to?}",
+            "{type?: speaker|browsed|kiosk, loop?: bool, noNarration?, noAnimation?, useTimings?, showMediaControls?, from?, to?}",
             has_doc,
             setup
         ),
@@ -240,6 +240,9 @@ fn setup(s: &mut Session, p: &Value) -> Result<Value> {
         if let Some(v) = bool_param(p, "useTimings") {
             sh.use_timings = v;
         }
+        if let Some(v) = bool_param(p, "showMediaControls") {
+            sh.show_media_controls = v;
+        }
         match (p.get("from").and_then(Value::as_u64), p.get("to").and_then(Value::as_u64)) {
             (Some(a), Some(b)) => sh.range = Some((a.min(u32::MAX as u64) as u32, b.min(u32::MAX as u64) as u32)),
             (None, None) if p.get("all").is_some() => sh.range = None,
@@ -264,3 +267,22 @@ fn custom_show(s: &mut Session, p: &Value) -> Result<Value> {
     })?;
     ok()
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn show_media_controls_follow_setup() {
+        let mut s = Session::with_new();
+        assert!(s.doc().expect("doc").doc.show.show_media_controls);
+        let off = s.execute("show.setup", &json!({"showMediaControls": false})).expect("off");
+        assert_eq!(off["showMediaControls"], false);
+        assert_eq!(off["useTimings"], true, "other setup flags stay");
+        let timings = s.execute("show.setup", &json!({"useTimings": false})).expect("timings");
+        assert_eq!(timings["showMediaControls"], false);
+        assert_eq!(timings["useTimings"], false);
+        s.execute("show.setup", &json!({"showMediaControls": true})).expect("on");
+        assert!(s.doc().expect("doc").doc.show.show_media_controls);
+    }
+}