Make FileStat have millisecond precisions, for linux, mac and android.

sdk/lib/io/file_system_entity.dart

Index: sdk/lib/io/file_system_entity.dart
diff --git a/sdk/lib/io/file_system_entity.dart b/sdk/lib/io/file_system_entity.dart
index 3f0cf7c6009cbd76893609138443c2bf4306497b..adf82455b3e7b5ab68eac208ac3e5fe4ba3526cb 100644
--- a/sdk/lib/io/file_system_entity.dart
+++ b/sdk/lib/io/file_system_entity.dart
@@ -104,9 +104,9 @@ class FileStat {
     var data = _statSync(path);
     if (data is OSError) return FileStat._notFound;
     return new FileStat._internal(
-        new DateTime.fromMillisecondsSinceEpoch(data[_CHANGED_TIME] * 1000),
-        new DateTime.fromMillisecondsSinceEpoch(data[_MODIFIED_TIME] * 1000),
-        new DateTime.fromMillisecondsSinceEpoch(data[_ACCESSED_TIME] * 1000),
+        new DateTime.fromMillisecondsSinceEpoch(data[_CHANGED_TIME]),
+        new DateTime.fromMillisecondsSinceEpoch(data[_MODIFIED_TIME]),
+        new DateTime.fromMillisecondsSinceEpoch(data[_ACCESSED_TIME]),
         FileSystemEntityType._lookup(data[_TYPE]),
         data[_MODE],
         data[_SIZE]);
@@ -131,9 +131,9 @@ class FileStat {
       // Unwrap the real list from the "I'm not an error" wrapper.
       List data = response[1];
       return new FileStat._internal(
-          new DateTime.fromMillisecondsSinceEpoch(data[_CHANGED_TIME] * 1000),
-          new DateTime.fromMillisecondsSinceEpoch(data[_MODIFIED_TIME] * 1000),
-          new DateTime.fromMillisecondsSinceEpoch(data[_ACCESSED_TIME] * 1000),
+          new DateTime.fromMillisecondsSinceEpoch(data[_CHANGED_TIME]),
+          new DateTime.fromMillisecondsSinceEpoch(data[_MODIFIED_TIME]),
+          new DateTime.fromMillisecondsSinceEpoch(data[_ACCESSED_TIME]),
           FileSystemEntityType._lookup(data[_TYPE]),
           data[_MODE],
           data[_SIZE]);