Rename Date to DateTime.

runtime/lib/date_patch.dart

Index: runtime/lib/date_patch.dart
diff --git a/runtime/lib/date_patch.dart b/runtime/lib/date_patch.dart
index 349245e7491c074d49280756c487e29e43b3f1a3..8eb95f56854a018074b150e865e67caba54111c0 100644
--- a/runtime/lib/date_patch.dart
+++ b/runtime/lib/date_patch.dart
@@ -75,8 +75,8 @@ patch class _DateImpl {
     int daysSince1970 =
         _flooredDivision(_localDateInUtcMs, Duration.MILLISECONDS_PER_DAY);
     // 1970-1-1 was a Thursday.
-    return ((daysSince1970 + Date.THU - Date.MON) % Date.DAYS_IN_WEEK) +
-        Date.MON;
+    return ((daysSince1970 + DateTime.THU - DateTime.MON) % DateTime.DAYS_IN_WEEK) +
+        DateTime.MON;
   }
 
 
@@ -140,10 +140,10 @@ patch class _DateImpl {
    * as [this].
    *
    * Say [:t:] is the result of this function, then
-   * * [:this.year == new Date.fromMillisecondsSinceEpoch(t, true).year:],
-   * * [:this.month == new Date.fromMillisecondsSinceEpoch(t, true).month:],
-   * * [:this.day == new Date.fromMillisecondsSinceEpoch(t, true).day:],
-   * * [:this.hour == new Date.fromMillisecondsSinceEpoch(t, true).hour:],
+   * * [:this.year == new DateTime.fromMillisecondsSinceEpoch(t, true).year:],
+   * * [:this.month == new DateTime.fromMillisecondsSinceEpoch(t, true).month:],
+   * * [:this.day == new DateTime.fromMillisecondsSinceEpoch(t, true).day:],
+   * * [:this.hour == new DateTime.fromMillisecondsSinceEpoch(t, true).hour:],
    * * ...
    *
    * Daylight savings is computed as if the date was computed in [1970..2037].