Add a validator that tests the size of pub packages.

utils/pub/validator.dart

Index: utils/pub/validator.dart
diff --git a/utils/pub/validator.dart b/utils/pub/validator.dart
index 2dd5420fe66d335b2737d41819864d26e84f6c4d..72f65d1b3249e1630c79d4f2897e98e65b7b7748 100644
--- a/utils/pub/validator.dart
+++ b/utils/pub/validator.dart
@@ -18,6 +18,7 @@ import 'validator/lib.dart';
 import 'validator/license.dart';
 import 'validator/name.dart';
 import 'validator/pubspec_field.dart';
+import 'validator/size.dart';
 import 'validator/utf8_readme.dart';
 
 /// The base class for validators that check whether a package is fit for
@@ -44,8 +45,12 @@ abstract class Validator {
   /// Run all validators on the [entrypoint] package and print their results.
   /// The future will complete with the error and warning messages,
   /// respectively.
+  ///
+  /// [packageSize], if passed, should complete to the size of the tarred
+  /// package, in bytes. This is used to validate that it's not too big to
+  /// upload to the server.
   static Future<Pair<List<String>, List<String>>> runAll(
-      Entrypoint entrypoint) {
+      Entrypoint entrypoint, [Future<int> packageSize]) {
     var validators = [
       new LibValidator(entrypoint),
       new LicenseValidator(entrypoint),
@@ -56,6 +61,9 @@ abstract class Validator {
       new CompiledDartdocValidator(entrypoint),
       new Utf8ReadmeValidator(entrypoint)
     ];
+    if (packageSize != null) {
+      validators.add(new SizeValidator(entrypoint, packageSize));
+    }
 
     return Future.wait(validators.map((validator) => validator.validate()))
       .then((_) {