Make pub publish more user friendly:

utils/pub/path.dart

Index: utils/pub/path.dart
diff --git a/utils/pub/path.dart b/utils/pub/path.dart
index d803fd17075726750cd3c559d4731ff6478af52b..8f9f9a49b89afa9d5e879ec796ced39ff738d5b9 100644
--- a/utils/pub/path.dart
+++ b/utils/pub/path.dart
@@ -110,6 +110,19 @@ String normalize(String path) => _builder.normalize(path);
 ///     path.relative(r'D:\other'); // -> 'D:\other'
 String relative(String path) => _builder.relative(path);
 
+/// Splits [path] along separators and returns a [List] of the parts. The
+/// path will *not* be normalized before splitting.
+///
+///     path.split('a/b/c.txt'); // -> ['a', 'b', 'c.txt']
+///     path.split('a/../c');    // -> ['a', '..', 'c']
+///
+/// If [path] is absolute, the root prefix will be included in the first
+/// part.
+///
+///     path.split('/a/b/c.txt');    // -> ['/a', 'b', 'c.txt']
+///     path.split(r'C:\a\b\c.txt'); // -> [r'C:\a', 'b', 'c.txt']
+List<String> split(String path) => _builder.split(path);
+
 /// Removes a trailing extension from the last part of [path].
 ///
 ///     withoutExtension('path/to/foo.dart'); // -> 'path/to/foo'
@@ -329,6 +342,29 @@ class Builder {
     return pathParsed.toString();
   }
 
+  /// Splits [path] along separators and returns a [List] of the parts. The
+  /// path will *not* be normalized before splitting.
+  ///
+  ///     builder.split('a/b/c.txt'); // -> ['a', 'b', 'c.txt']
+  ///     builder.split('a/../c');    // -> ['a', '..', 'c']
+  ///
+  /// If [path] is absolute, the root prefix will be included in the first
+  /// part.
+  ///
+  ///     builder.split('/a/b/c.txt');    // -> ['/a', 'b', 'c.txt']
+  ///     builder.split(r'C:\a\b\c.txt'); // -> [r'C:\a', 'b', 'c.txt']
+  List<String> split(String path) {
+    var parsed = _parse(path);
+
+    // Include the root prefix in the first part.
+    if (parsed.root != null) {
+      if (parsed.parts.isEmpty) return [parsed.root];
+      parsed.parts[0] = '${parsed.root}${parsed.parts[0]}';
+    }
+
+    return parsed.parts.filter(((part) => part != ''));
+  }
+
   /// Removes a trailing extension from the last part of [path].
   ///
   ///     builder.withoutExtension('path/to/foo.dart'); // -> 'path/to/foo'