Make first and last getters.

samples/ui_lib/touch/Momentum.dart

Index: samples/ui_lib/touch/Momentum.dart
diff --git a/samples/ui_lib/touch/Momentum.dart b/samples/ui_lib/touch/Momentum.dart
index eb13ac70b9cc2d341a3049caa7f6849e321403e6..269b722e5b4f4a34eea6a36cc04aa2a3f8b9131f 100644
--- a/samples/ui_lib/touch/Momentum.dart
+++ b/samples/ui_lib/touch/Momentum.dart
@@ -456,7 +456,7 @@ class TimeoutMomentum implements Momentum {
     if (!physicsX.isDone() || !physicsY.isDone()) {
       _calculateMoves();
       if (!_moves.isEmpty) {
-        num firstTime = _moves.first().time;
+        num firstTime = _moves.first.time;
         _stepTimeout = Env.requestAnimationFrame(
             _step, null, firstTime);
         _decelerating = true;
@@ -490,8 +490,8 @@ class TimeoutMomentum implements Momentum {
     // Prune moves that are more than 1 frame behind when we have more
     // available moves.
     num lastEpoch = timestamp - SingleDimensionPhysics._MS_PER_FRAME;
-    while (!_moves.isEmpty && _moves.first() !== _moves.last()
-        && _moves.first().time < lastEpoch) {
+    while (!_moves.isEmpty && _moves.first !== _moves.last
+        && _moves.first.time < lastEpoch) {
       _moves.removeFirst();
     }
 
@@ -499,7 +499,7 @@ class TimeoutMomentum implements Momentum {
       final move = _moves.removeFirst();
       _delegate.onDecelerate(move.x, move.y);
       if (!_moves.isEmpty) {
-        num nextTime = _moves.first().time;
+        num nextTime = _moves.first.time;
         assert(_stepTimeout === null);
         _stepTimeout = Env.requestAnimationFrame(_step, null, nextTime);
       } else {
@@ -522,7 +522,7 @@ class TimeoutMomentum implements Momentum {
     _decelerating = false;
     Coordinate velocity;
     if (!_moves.isEmpty) {
-      final move = _moves.first();
+      final move = _moves.first;
       // This is a workaround for the ugly hacks that get applied when a user
       // passed a velocity in to this Momentum implementation.
       num velocityScale = SingleDimensionPhysics._MS_PER_FRAME *
@@ -545,7 +545,7 @@ class TimeoutMomentum implements Momentum {
 
   Coordinate get destination {
     if (!_moves.isEmpty) {
-      final lastMove = _moves.last();
+      final lastMove = _moves.last;
       return new Coordinate(lastMove.x, lastMove.y);
     } else {
       return null;