Rename Date to DateTime.

samples/clock/web/clock.dart

Index: samples/clock/web/clock.dart
diff --git a/samples/clock/web/clock.dart b/samples/clock/web/clock.dart
index 9a90c2e0b731655b2c37340cd2815f3a6cca3c3b..ebf3dc957819ef27c5a5bd059151548dbfd9c232 100644
--- a/samples/clock/web/clock.dart
+++ b/samples/clock/web/clock.dart
@@ -47,18 +47,18 @@ class CountDownClock {
 
     createNumbers(parent, parent.clientWidth, parent.clientHeight);
 
-    updateTime(new Date.now());
+    updateTime(new DateTime.now());
 
     window.requestAnimationFrame(tick);
   }
 
   void tick(num time) {
-    updateTime(new Date.now());
+    updateTime(new DateTime.now());
     balls.tick(time);
     window.requestAnimationFrame(tick);
   }
 
-  void updateTime(Date now) {
+  void updateTime(DateTime now) {
     if (now.hour != displayedHour) {
       setDigits(pad2(now.hour), hours);
       displayedHour = now.hour;