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 9d906b7b15862fdd709e6813c59ade74336cc86e..b4dbc415d4b890344c74cd8bd5e0b006c330ee11 100644
--- a/sdk/lib/_internal/dartdoc/lib/dartdoc.dart
+++ b/sdk/lib/_internal/dartdoc/lib/dartdoc.dart
@@ -305,7 +305,7 @@ 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);
@@ -1826,7 +1826,7 @@ 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);