Auto merge of #24885 - shnmorimoto:implement_mediasession_set_positon_state, r=ferjm

Implement mediasession set positon state

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fix #24808

> Bonus points if you want to tweak the existing UI by adding a progress bar, and the info about the current position and total duration.

I haven't implemented this yet.

---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #24808 (GitHub issue number if applicable)

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- [x] There are tests for these changes OR

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components/script/dom/htmlmediaelement.rs

@@ -67,7 +67,7 @@ use crate::script_thread::ScriptThread;
 use crate::task_source::TaskSource;
 use dom_struct::dom_struct;
 use embedder_traits::resources::{self, Resource as EmbedderResource};
-use embedder_traits::{MediaSessionEvent, MediaSessionPlaybackState};
+use embedder_traits::{MediaPositionState, MediaSessionEvent, MediaSessionPlaybackState};
 use euclid::default::Size2D;
 use headers::{ContentLength, ContentRange, HeaderMapExt};
 use html5ever::{LocalName, Prefix};
@@ -1780,6 +1780,15 @@ impl HTMLMediaElement {
                     .add(self.playback_position.get(), position);
                 self.playback_position.set(position);
                 self.time_marches_on();
+                let media_position_state =
+                    MediaPositionState::new(self.duration.get(), self.playbackRate.get(), position);
+                debug!(
+                    "Sending media session event set position state {:?}",
+                    media_position_state
+                );
+                self.send_media_session_event(MediaSessionEvent::SetPositionState(
+                    media_position_state,
+                ));
             },
             PlayerEvent::SeekData(p, ref seek_lock) => {
                 self.fetch_request(Some(p), Some(seek_lock.clone()));
@@ -1925,6 +1934,18 @@ impl HTMLMediaElement {
 
         media_session.send_event(event);
     }
+
+    pub fn set_duration(&self, duration: f64) {
+        self.duration.set(duration);
+    }
+
+    pub fn reset(&self) {
+        if let Some(ref player) = *self.player.borrow() {
+            if let Err(e) = player.lock().unwrap().stop() {
+                eprintln!("Could not stop player {:?}", e);
+            }
+        }
+    }
 }
 
 // XXX Placeholder for [https://github.com/servo/servo/issues/22293]