Update pub to use new import syntax.

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 3c4963419b877876a2e4b988067cd437f486b99f..330ca5b5fc1b13f0efe3f2a85870ce890b6a7312 100644
--- a/utils/pub/hosted_source.dart
+++ b/utils/pub/hosted_source.dart
@@ -2,19 +2,19 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-#library('hosted_source');
-
-#import('dart:io', prefix: 'io');
-#import('dart:json');
-#import('dart:uri');
-
-#import('io.dart');
-#import('package.dart');
-#import('pubspec.dart');
-#import('source.dart');
-#import('source_registry.dart');
-#import('utils.dart');
-#import('version.dart');
+library hosted_source;
+
+import 'dart:io' as io;
+import 'dart:json';
+import 'dart:uri';
+
+import 'io.dart';
+import 'package.dart';
+import 'pubspec.dart';
+import 'source.dart';
+import 'source_registry.dart';
+import 'utils.dart';
+import 'version.dart';
 
 /**
  * A package source that installs packages from a package hosting site that