Get rid of old redundant methods in io.dart.

utils/pub/command_lish.dart

Index: utils/pub/command_lish.dart
diff --git a/utils/pub/command_lish.dart b/utils/pub/command_lish.dart
index d3a2cb4bf67aca21851b9a193626036be19a6081..f2e5f0529234ea30d9bb58c2d95fecb82d9943ba 100644
--- a/utils/pub/command_lish.dart
+++ b/utils/pub/command_lish.dart
@@ -146,15 +146,15 @@ class LishCommand extends PubCommand {
       return listDir(rootDir, recursive: true).then((entries) {
         return entries
             .where(fileExists) // Skip directories.
-            .map((entry) => relativeTo(entry, rootDir));
+            .map((entry) => path.relative(entry, from: rootDir));
       });
     }).then((files) => files.where(_shouldPublish).toList());
   }
 
   /// Returns `true` if [file] should be published.
   bool _shouldPublish(String file) {
-    if (_BLACKLISTED_FILES.contains(basename(file))) return false;
-    return !splitPath(file).any(_BLACKLISTED_DIRS.contains);
+    if (_BLACKLISTED_FILES.contains(path.basename(file))) return false;
+    return !path.split(file).any(_BLACKLISTED_DIRS.contains);
   }
 
   /// Returns the value associated with [key] in [map]. Throws a user-friendly