Transform async code only for source libraries.

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

Index: pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
index b7ec22eb16116749c8b57b6734065754180da33f..b0b24bc09d11b2ca1908e20022d0cedaed349b3e 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
@@ -40,6 +40,7 @@ import 'package:kernel/ast.dart'
         VariableGet,
         VoidType;
 
+import 'package:kernel/core_types.dart';

[ahe, 2017/05/24 12:15:55]

Please use show.

[scheglov, 2017/05/24 22:45:50]

Done.

 import 'package:kernel/transformations/erasure.dart' show Erasure;
 
 import 'package:kernel/transformations/continuation.dart' as transformAsync;
@@ -670,8 +671,8 @@ class KernelTarget extends TargetImplementation {
       _program.accept(new Erasure());
       ticker.logMs("Erased type variables in generic methods");
     }
-    // TODO(kmillikin): Make this run on a per-method basis.

[ahe, 2017/05/24 12:15:55]

I think this TODO still applies.

[scheglov, 2017/05/24 22:45:50]

Done.

-    transformAsync.transformProgram(_program);
+    var coreTypes = new CoreTypes(_program);
+    transformAsync.transformLibraries(coreTypes, loader.libraries);
     ticker.logMs("Transformed async methods");
   }