servo: Merge #6894 - style: Switch animation timestamps to be doubles instead of floats (from pcwalton:double-precision-timestamps); r=metajack

32-bit floats are not enough to hold timestamps since the epoch and
result in jank.

r? @metajack

Source-Repo: https://github.com/servo/servo
Source-Revision: 92cbb9368471d12f0d5492abd7e04b16df549366

servo/components/script/layout_interface.rs

@@ -208,15 +208,15 @@ pub struct Animation {
     /// A description of the property animation that is occurring.
     pub property_animation: PropertyAnimation,
     /// The start time of the animation, as returned by `time::precise_time_s()`.
-    pub start_time: f32,
+    pub start_time: f64,
     /// The end time of the animation, as returned by `time::precise_time_s()`.
-    pub end_time: f32,
+    pub end_time: f64,
 }
 
 impl Animation {
     /// Returns the duration of this animation in seconds.
     #[inline]
-    pub fn duration(&self) -> f32 {
+    pub fn duration(&self) -> f64 {
         self.end_time - self.start_time
     }
 }