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

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

Index: sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback/transformer_isolate.dart b/sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart
similarity index 86%
copy from sdk/lib/_internal/pub/lib/src/barback/transformer_isolate.dart
copy to sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart
index 65ba68f72ebe588c95c790b570093f8c6cfd97ba..04298d2be1fb066311f30868801f2e26bb699dcf 100644
--- a/sdk/lib/_internal/pub/lib/src/barback/transformer_isolate.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/barback/transformer_isolate.dart
@@ -50,8 +50,7 @@ class TransformerIsolate {
   /// exists. Otherwise, a snapshot of the isolate's code will be saved to that
   /// path once the isolate is loaded.
   static Future<TransformerIsolate> spawn(AssetEnvironment environment,
-      BarbackServer transformerServer, List<TransformerId> ids,
-      {String snapshot}) {
+      BarbackServer transformerServer, List<TransformerId> ids, {String snapshot}) {
     return mapFromIterableAsync(ids, value: (id) {
       return id.getAssetId(environment.barback);
     }).then((idsToAssetIds) {
@@ -75,11 +74,11 @@ class TransformerIsolate {
       log.fine("Loading transformers from $ids");
 
       var port = new ReceivePort();
-      return dart.runInIsolate(code.toString(), port.sendPort,
-              packageRoot: baseUrl.resolve('packages'),
-              snapshot: snapshot)
-          .then((_) => port.first)
-          .then((sendPort) {
+      return dart.runInIsolate(
+          code.toString(),
+          port.sendPort,
+          packageRoot: baseUrl.resolve('packages'),
+          snapshot: snapshot).then((_) => port.first).then((sendPort) {
         return new TransformerIsolate._(sendPort, environment.mode, idsToUrls);
       }).catchError((error, stackTrace) {
         if (error is! CrossIsolateException) throw error;
@@ -92,18 +91,17 @@ class TransformerIsolate {
         // The isolate error message contains the fully expanded path, not the
         // "package:" URI, so we have to be liberal in what we look for in the
         // error message.
-        var missingTransformer = idsToUrls.keys.firstWhere((id) =>
-            firstErrorLine.startsWith(
-                "Uncaught Error: Load Error: Failure getting ") &&
-            firstErrorLine.contains(idsToUrls[id].path),
+        var missingTransformer = idsToUrls.keys.firstWhere(
+            (id) =>
+                firstErrorLine.startsWith("Uncaught Error: Load Error: Failure getting ") &&
+                    firstErrorLine.contains(idsToUrls[id].path),
             orElse: () => throw error);
         var packageUri = idToPackageUri(idsToAssetIds[missingTransformer]);
 
         // If there was an IsolateSpawnException and the import that actually
         // failed was the one we were loading transformers from, throw an
         // application exception with a more user-friendly message.
-        fail('Transformer library "$packageUri" not found.',
-            error, stackTrace);
+        fail('Transformer library "$packageUri" not found.', error, stackTrace);
       });
     });
   }
@@ -122,8 +120,7 @@ class TransformerIsolate {
       'configuration': JSON.encode(config.configuration)
     }).then((transformers) {
       transformers = transformers.map(
-          (transformer) => deserializeTransformerLike(transformer, config))
-          .toSet();
+          (transformer) => deserializeTransformerLike(transformer, config)).toSet();
       log.fine("Transformers from $config: $transformers");
       return transformers;
     }).catchError((error, stackTrace) {
@@ -133,8 +130,8 @@ class TransformerIsolate {
 }
 
 /// An error thrown when a transformer fails to load.
-class TransformerLoadError extends SourceSpanException
-    implements WrappedException {
+class TransformerLoadError extends SourceSpanException implements
+    WrappedException {
   final CrossIsolateException innerError;
   Chain get innerChain => innerError.stackTrace;