Make listDir and createSymlink synchronous in pub.

utils/pub/package.dart

Index: utils/pub/package.dart
diff --git a/utils/pub/package.dart b/utils/pub/package.dart
index 1bc7445869c2c1e4dcc8aa8f5a9db9cb56f8da19..d3d9819088ce9d30a76baab19871991b658034f0 100644
--- a/utils/pub/package.dart
+++ b/utils/pub/package.dart
@@ -43,20 +43,18 @@ class Package {
   /// same conventions as pub.dartlang.org for choosing the primary one: the
   /// README with the fewest extensions that is lexically ordered first is
   /// chosen.
-  Future<String> get readmePath {
-    return listDir(dir).then((entries) {
-      var readmes = entries.map(path.basename).
-          where((entry) => entry.contains(_README_REGEXP));
-      if (readmes.isEmpty) return;
-
-      return path.join(dir, readmes.min((readme1, readme2) {
-        var extensions1 = ".".allMatches(readme1).length;
-        var extensions2 = ".".allMatches(readme2).length;
-        var comparison = extensions1.compareTo(extensions2);
-        if (comparison != 0) return comparison;
-        return readme1.compareTo(readme2);
-      }));
-    });
+  String get readmePath {
+    var readmes = listDir(dir).map(path.basename).
+        where((entry) => entry.contains(_README_REGEXP));
+    if (readmes.isEmpty) return;
+
+    return path.join(dir, readmes.min((readme1, readme2) {
+      var extensions1 = ".".allMatches(readme1).length;
+      var extensions2 = ".".allMatches(readme2).length;
+      var comparison = extensions1.compareTo(extensions2);
+      if (comparison != 0) return comparison;
+      return readme1.compareTo(readme2);
+    }));
   }
 
   /// Loads the package whose root directory is [packageDir]. [name] is the