core: `Player` should start in the `Idle` phase

core/src/frame_lifecycle.rs

@@ -69,6 +69,12 @@ pub enum FramePhase {
     Idle,
 }
 
+impl Default for FramePhase {
+    fn default() -> Self {
+        FramePhase::Idle
+    }
+}
+
 /// Run one frame according to AVM1 frame order.
 pub fn run_all_phases_avm1<'gc>(context: &mut UpdateContext<'_, 'gc, '_>) {
     // In AVM1, we only ever execute the update phase, and all the work that

core/src/player.rs

@@ -1877,7 +1877,7 @@ impl PlayerBuilder {
 
                 // Timing
                 frame_rate,
-                frame_phase: FramePhase::Enter,
+                frame_phase: Default::default(),
                 frame_accumulator: 0.0,
                 recent_run_frame_timings: VecDeque::with_capacity(10),
                 start_time: Instant::now(),