timeline: use impl Into<Chain<T>> on set_chain

This removes the requirement for animation chains to have the
`into()` method call before passing itself into `set_chain`.

Author: 13r0ck

examples/counter/src/main.rs

@@ -83,7 +83,7 @@ impl Application for Counter {
         // cosmic-time assumes that the timeline is continuous. Try deleting it,
         // the height will animate smoothly from 300 to 150 right through keyframe `four`!
 
-        timeline.set_chain(animation.into()).start();
+        timeline.set_chain(animation).start();
         // `Start` is very important! Your animation won't "start" without it.
         // Cosmic-time tries to be atomic, meaning that keyframes defined in the
         // same function call all start at the same time. Because there is process time

examples/pokedex/src/main.rs

@@ -271,7 +271,7 @@ impl Pokemon {
             .loop_forever();
 
         // println!("Animating wth ease: {ease:?}"); // Uncomment to see the type of easing
-        timeline.set_chain(animation.into()).start();
+        timeline.set_chain(animation).start();
 
         Ok(Pokemon {
             timeline,

examples/stopwatch/src/main.rs

@@ -66,13 +66,11 @@ impl Application for Stopwatch {
                     self.state = State::Ticking {
                         last_tick: Instant::now(),
                     };
-                    self.timeline
-                        .set_chain(anim_to_destructive().into())
-                        .start();
+                    self.timeline.set_chain(anim_to_destructive()).start();
                 }
                 State::Ticking { .. } => {
                     self.state = State::Idle;
-                    self.timeline.set_chain(anim_to_primary().into()).start();
+                    self.timeline.set_chain(anim_to_primary()).start();
                 }
             },
             Message::Tick(now) => {

src/timeline.rs

@@ -157,10 +157,11 @@ impl Timeline {
     }
 
     /// Destructure keyframe into subtracks (via impl ExactSizeIterator) and add to timeline.
-    pub fn set_chain<T>(&mut self, chain: Chain<T>) -> &mut Self
+    pub fn set_chain<T>(&mut self, chain: impl Into<Chain<T>>) -> &mut Self
     where
         T: ExactSizeIterator<Item = Option<DurFrame>> + std::fmt::Debug,
     {
+        let chain: Chain<T> = chain.into();
         let id = chain.id.clone();
         let repeat = chain.repeat;
         let mut tracks: Vec<Vec<DurFrame>> = Vec::new();

src/widget/toggler.rs

@@ -8,8 +8,8 @@ use iced_native::text;
 use iced_native::time::Duration;
 use iced_native::widget::{self, Row, Text, Tree};
 use iced_native::{
-    color, Alignment, Clipboard, Color, Element, Event, Layout, Length, Pixels, Point,
-    Rectangle, Shell, Widget,
+    color, Alignment, Clipboard, Color, Element, Event, Layout, Length, Pixels, Point, Rectangle,
+    Shell, Widget,
 };
 
 use crate::keyframes::{self, toggler::Chain};