Switch pkg packages, pub, and dartdoc to use package: imports.

utils/pub/hosted_source.dart

Index: utils/pub/hosted_source.dart
diff --git a/utils/pub/hosted_source.dart b/utils/pub/hosted_source.dart
index bb4345c0761817aaa1a08697f1b3d2da63a7b1e9..f27c3efac3c731078a898539e85bc68ffbf51a69 100644
--- a/utils/pub/hosted_source.dart
+++ b/utils/pub/hosted_source.dart
@@ -10,8 +10,8 @@ import 'dart:json' as json;
 import 'dart:uri';
 
 // TODO(nweiz): Make this import better.
-import '../../pkg/http/lib/http.dart' as http;
-import '../../pkg/pathos/lib/path.dart' as path;
+import 'package:http/http.dart' as http;
+import 'package:pathos/path.dart' as path;
 
 import 'http.dart';
 import 'io.dart';