Rename Date to DateTime.

sdk/lib/_internal/dartdoc/lib/dartdoc.dart

Index: sdk/lib/_internal/dartdoc/lib/dartdoc.dart
diff --git a/sdk/lib/_internal/dartdoc/lib/dartdoc.dart b/sdk/lib/_internal/dartdoc/lib/dartdoc.dart
index 772e9d0c64a3727a768461f6c3d4cf7fa1d8b1b7..f1620d010ed93d66b120661102986a29bc2e0ab7 100644
--- a/sdk/lib/_internal/dartdoc/lib/dartdoc.dart
+++ b/sdk/lib/_internal/dartdoc/lib/dartdoc.dart
@@ -306,7 +306,7 @@ class Dartdoc {
   String get footerContent{
     var footerItems = [];
     if (!omitGenerationTime) {
-      footerItems.add("This page was generated at ${new Date.now()}");
+      footerItems.add("This page was generated at ${new DateTime.now()}");
     }
     if (footerText != null) {
       footerItems.add(footerText);
@@ -1827,7 +1827,7 @@ class Dartdoc {
     }
     startFile('appcache.manifest');
     write("CACHE MANIFEST\n\n");
-    write("# VERSION: ${new Date.now()}\n\n");
+    write("# VERSION: ${new DateTime.now()}\n\n");
     write("NETWORK:\n*\n\n");
     write("CACHE:\n");
     var toCache = new Directory.fromPath(outputDir);