[Effen] Reduce splashes when scrolling.

sky/framework/animation/animated_value.dart

Index: sky/framework/animation/animated_value.dart
diff --git a/sky/framework/animation/animated_value.dart b/sky/framework/animation/animated_value.dart
index 11f1dea27197fb3892ee5d9319478a5c3ab8d247..d07dac5646191c465fd2f2539a8581d0ae1ee61f 100644
--- a/sky/framework/animation/animated_value.dart
+++ b/sky/framework/animation/animated_value.dart
@@ -67,4 +67,11 @@ class AnimatedValue {
     _completer = new Completer();
     return _completer.future;
   }
+
+  double get remainingTime {
+    if (_animation == null)
+      return 0.0;
+    return _animation.remainingTime;
+  }
+
 }