Revert "Use native async/await support in pub."

sdk/lib/_internal/pub_generated/lib/src/barback/excluding_transformer.dart

Index: sdk/lib/_internal/pub_generated/lib/src/barback/excluding_transformer.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback/excluding_transformer.dart b/sdk/lib/_internal/pub_generated/lib/src/barback/excluding_transformer.dart
similarity index 92%
copy from sdk/lib/_internal/pub/lib/src/barback/excluding_transformer.dart
copy to sdk/lib/_internal/pub_generated/lib/src/barback/excluding_transformer.dart
index 90b4e512c671b62a1f3e3f91ab7d77bcbeb89c35..52d90a991d2d9760ee5115fe4c248c2bd9ac02e5 100644
--- a/sdk/lib/_internal/pub/lib/src/barback/excluding_transformer.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/barback/excluding_transformer.dart
@@ -25,7 +25,8 @@ class ExcludingTransformer extends Transformer {
       return new _LazyExcludingTransformer(inner as LazyTransformer, config);
     } else if (inner is DeclaringTransformer) {
       return new _DeclaringExcludingTransformer(
-          inner as DeclaringTransformer, config);
+          inner as DeclaringTransformer,
+          config);
     } else {
       return new ExcludingTransformer._(inner, config);
     }
@@ -48,10 +49,10 @@ class ExcludingTransformer extends Transformer {
   String toString() => _inner.toString();
 }
 
-class _DeclaringExcludingTransformer extends ExcludingTransformer
-    implements DeclaringTransformer {
+class _DeclaringExcludingTransformer extends ExcludingTransformer implements
+    DeclaringTransformer {
   _DeclaringExcludingTransformer(DeclaringTransformer inner,
-          TransformerConfig config)
+      TransformerConfig config)
       : super._(inner as Transformer, config);
 
   Future declareOutputs(DeclaringTransform transform) =>
@@ -61,6 +62,6 @@ class _DeclaringExcludingTransformer extends ExcludingTransformer
 class _LazyExcludingTransformer extends _DeclaringExcludingTransformer
     implements LazyTransformer {
   _LazyExcludingTransformer(DeclaringTransformer inner,
-          TransformerConfig config)
+      TransformerConfig config)
       : super(inner, config);
 }