Allow clocks to be bindable and inherited down the logical tree.

src/Avalonia.Animation/Animatable.cs

@@ -18,25 +18,10 @@ namespace Avalonia.Animation
         public static readonly StyledProperty<IClock> ClockProperty =
             AvaloniaProperty.Register<Animatable, IClock>(nameof(Clock), inherits: true);
 
-        /// <summary>
-        /// Defines the <see cref="PlayState"/> property.
-        /// </summary>
-        public static readonly DirectProperty<Animatable, PlayState> PlayStateProperty =
-            AvaloniaProperty.RegisterDirect<Animatable, PlayState>(
-                nameof(PlayState),
-                o => o.PlayState,
-                (o, v) => o.PlayState = v);
-
-        private PlayState _playState = PlayState.Run;
-
-        /// <summary>
-        /// Gets or sets the state of the animation for this
-        /// control.
-        /// </summary>
-        public PlayState PlayState
+        public IClock Clock
         {
-            get { return _playState; }
-            set { SetAndRaise(PlayStateProperty, ref _playState, value); }
+            get => GetValue(ClockProperty);
+            set => SetValue(ClockProperty, value);
         }
 
         /// <summary>
@@ -72,7 +57,7 @@ namespace Avalonia.Animation
 
                 if (match != null)
                 {
-                    match.Apply(this, Clock.GlobalClock, e.OldValue, e.NewValue);
+                    match.Apply(this, Clock ?? Avalonia.Animation.Clock.GlobalClock, e.OldValue, e.NewValue);
                 }
             }
         }

src/Avalonia.Animation/AnimationInstance`1.cs

@@ -34,7 +34,7 @@ namespace Avalonia.Animation
         private Action _onCompleteAction;
         private Func<double, T, T> _interpolator;
         private IDisposable _timerSubscription;
-        private readonly Clock _clock;
+        private readonly IClock _clock;
 
         public AnimationInstance(Animation animation, Animatable control, Animator<T> animator, Clock clock, Action OnComplete, Func<double, T, T> Interpolator)
         {
@@ -117,7 +117,7 @@ namespace Avalonia.Animation
 
         private void DoPlayStatesAndTime(TimeSpan systemTime)
         {
-            if (_clock.PlayState == PlayState.Stop || _targetControl.PlayState == PlayState.Stop)
+            if (_clock.PlayState == PlayState.Stop)
                 DoComplete();
 
             if (!_gotFirstKFValue)

src/Avalonia.Animation/TransitionInstance.cs

@@ -18,7 +18,7 @@ namespace Avalonia.Animation
         private IDisposable timerSubscription;
         private TimeSpan startTime;
         private TimeSpan duration;
-        private readonly Clock _clock;
+        private readonly IClock _clock;
 
         public TransitionInstance(Clock clock, TimeSpan Duration)
         {

src/Avalonia.Styling/Styling/Style.cs

@@ -111,17 +111,20 @@ namespace Avalonia.Styling
                 {
                     var subs = GetSubscriptions(control);
 
-                    foreach (var animation in Animations)
+                    if (control is Animatable animatable)
                     {
-                        IObservable<bool> obsMatch = match.ObservableResult;
-
-                        if (match.ImmediateResult == true)
+                        foreach (var animation in Animations)
                         {
-                            obsMatch = Observable.Return(true);
-                        } 
+                            IObservable<bool> obsMatch = match.ObservableResult;
 
-                        var sub = animation.Apply((Animatable)control, Clock.GlobalClock, obsMatch);
-                        subs.Add(sub);
+                            if (match.ImmediateResult == true)
+                            {
+                                obsMatch = Observable.Return(true);
+                            }
+
+                            var sub = animation.Apply(animatable, animatable.Clock ?? Clock.GlobalClock, obsMatch);
+                            subs.Add(sub);
+                        } 
                     }
 
                     foreach (var setter in Setters)

src/Avalonia.Visuals/Animation/TransformAnimator.cs

@@ -12,7 +12,7 @@ namespace Avalonia.Animation
         DoubleAnimator childKeyFrames;
 
         /// <inheritdoc/>
-        public override IDisposable Apply(Animation animation, Animatable control, Clock clock, IObservable<bool> obsMatch, Action onComplete)
+        public override IDisposable Apply(Animation animation, Animatable control, IClock clock, IObservable<bool> obsMatch, Action onComplete)
         {
             var ctrl = (Visual)control;