Fix typos in sky-drawer and sky-scrollable

sky/framework/fling-curve.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import "dart:math" as math;
 
 const double _kDefaultAlpha = -5707.62;
 const double _kDefaultBeta = 172.0;
 const double _kDefaultGamma = 3.7;
 
 double _positionAtTime(double t) {
-  return kDefaultAlpha * math.exp(-kDefaultGamma * t) - kDefaultBeta * t - kDefaultAlpha;
+  return _kDefaultAlpha * math.exp(-_kDefaultGamma * t)
+      - _kDefaultBeta * t
+      - _kDefaultAlpha;
 }
 
 double _velocityAtTime(double t) {
-  return -kDefaultAlpha * kDefaultGamma * math.exp(-kDefaultGamma * t) - kDefaultBeta;
+  return -_kDefaultAlpha * _kDefaultGamma * math.exp(-_kDefaultGamma * t)
+      - _kDefaultBeta;
 }
 
 double _timeAtVelocity(double v) {
-  return -math.log((v + kDefaultBeta) / (-kDefaultAlpha * kDefaultGamma)) / kDefaultGamma;
+  return -math.log((v + _kDefaultBeta) / (-_kDefaultAlpha * _kDefaultGamma))
+      / _kDefaultGamma;
 }
 
 final double _kMaxVelocity = _velocityAtTime(0.0);
 final double _kCurveDuration = _timeAtVelocity(0.0);
 
 class FlingCurve {
   double _timeOffset;
   double _positionOffset;
   double _startTime;
   double _previousPosition;
@@ skipping 11 matching lines @@
   double update(double timeStamp) {
     double t = timeStamp / 1000.0 - _startTime + _timeOffset;
     if (t >= _kCurveDuration)
       return 0.0;
     double position = _positionAtTime(t) - _positionOffset;
     double positionDelta = position - _previousPosition;
     _previousPosition = position;
     return _direction * math.max(0.0, positionDelta);
   }
 }