Big merge from experimental to bleeding edge.

utils/pub/validator.dart

Index: utils/pub/validator.dart
diff --git a/utils/pub/validator.dart b/utils/pub/validator.dart
index 63a2386c07290ae3525efe93bc063900ce7e1e0c..70f5a9ffa24041516d974630a760b95aea26953f 100644
--- a/utils/pub/validator.dart
+++ b/utils/pub/validator.dart
@@ -55,10 +55,13 @@ abstract class Validator {
     // 3356, which causes a bug if all validators are (synchronously) using
     // Future.immediate and an error is thrown before a handler is set up.
     return sleep(0).chain((_) {
-      return Futures.wait(validators.map((validator) => validator.validate()));
-    }).transform((_) {
-      var errors = flatten(validators.map((validator) => validator.errors));
-      var warnings = flatten(validators.map((validator) => validator.warnings));
+      return Futures.wait(
+          validators.mappedBy((validator) => validator.validate()));
+    }).then((_) {
+      var errors =
+          flatten(validators.mappedBy((validator) => validator.errors));
+      var warnings =
+          flatten(validators.mappedBy((validator) => validator.warnings));
 
       if (!errors.isEmpty) {
         log.error("Missing requirements:");