Reapply "Use backend targets to run Kernel transformations in Fasta"

pkg/kernel/lib/target/vm_fasta.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+library kernel.target.vm_fasta;
+
+import '../ast.dart' show Program, Library;
+import '../core_types.dart' show CoreTypes;
+import '../class_hierarchy.dart' show ClassHierarchy;
+
+import '../transformations/mixin_full_resolution.dart' as transformMixins
+    show transformLibraries;
+import '../transformations/continuation.dart' as transformAsync
+    show transformLibraries;
+import '../transformations/erasure.dart' as tranformErasure
+    show transformLibraries;
+
+import 'targets.dart' show TargetFlags;
+import 'vm.dart' as vm_target;
+
+class VmFastaTarget extends vm_target.VmTarget {
+  VmFastaTarget(TargetFlags flags) : super(flags);
+
+  String get name => "vm_fasta";
+
+  void performModularTransformationsOnLibraries(
+      CoreTypes coreTypes, ClassHierarchy hierarchy, List<Library> libraries,
+      {void logger(String msg)}) {
+    transformMixins.transformLibraries(this, coreTypes, hierarchy, libraries);
+    logger?.call("Transformed mixin applications");
+
+    // TODO(ahe): Don't generate type variables in the first place.
+    if (!strongMode) {
+      tranformErasure.transformLibraries(coreTypes, libraries);
+      logger?.call("Erased type variables in generic methods");
+    }
+
+    // TODO(kmillikin): Make this run on a per-method basis.
+    transformAsync.transformLibraries(coreTypes, libraries);
+    logger?.call("Transformed async methods");
+  }
+
+  void performGlobalTransformations(CoreTypes coreTypes, Program program,
+      {void logger(String msg)}) {}
+}