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

pkg/kernel/lib/transformations/erasure.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.transformations.erasure;
 
 import '../ast.dart';
 import '../type_algebra.dart';
+import '../core_types.dart';
+
+Program transformProgram(CoreTypes coreTypes, Program program) {
+  program.accept(new Erasure());
+}
+
+void transformLibraries(CoreTypes coreTypes, List<Library> libraries) {
+  Erasure erasure = new Erasure();
+  for (Library library in libraries) {
+    library.accept(erasure);
+  }
+}
 
 /// This pass is a temporary measure to run strong mode code in the VM, which
 /// does not yet have the necessary runtime support.
 ///
 /// Function type parameter lists are cleared and all uses of a function type
 /// parameter are replaced by its upper bound.
 ///
 /// All uses of type parameters in constants are replaced by 'dynamic'.
 ///
 /// This does not preserve dynamic type safety.
@@ skipping 120 matching lines @@
   }
 
   @override
   visitMapLiteral(MapLiteral node) {
     if (node.isConst) pushConstantContext();
     node.transformChildren(this);
     if (node.isConst) popConstantContext();
     return node;
   }
 }