Transform async code only for source libraries.

pkg/kernel/lib/transformations/continuation.dart

Index: pkg/kernel/lib/transformations/continuation.dart
diff --git a/pkg/kernel/lib/transformations/continuation.dart b/pkg/kernel/lib/transformations/continuation.dart
index 72167987b2009382bbc9532e1c8ab8341261fc2e..1fd144ec44da05a87a70ad684d0199e318119eb0 100644
--- a/pkg/kernel/lib/transformations/continuation.dart
+++ b/pkg/kernel/lib/transformations/continuation.dart
@@ -12,10 +12,16 @@ import '../visitor.dart';
 
 import 'async.dart';
 
-Program transformProgram(Program program) {
+Program transformProgram(Program program,

[Siggi Cherem (dart-lang), 2017/05/23 22:06:17]

API design question for Kevin/Peter:

Would you rather have:
  Program transformProgram(Program program, filter);

Or

  void transformLibraries(List<Library> libraries);


I'm fine with either at this time, but have a slight preference for the latter
when it comes to modular transformations: you don't need a program if you are
applying a modular transformation.

(this relates to my general comment on the CL, we'll have similar API choice
when we switch to use Target.performModularTransformations.)

+    {bool libraryFilter(Library library)}) {
   var helper = new HelperNodes.fromProgram(program);
   var rewriter = new RecursiveContinuationRewriter(helper);
-  return rewriter.rewriteProgram(program);
+  for (var library in program.libraries) {
+    if (libraryFilter == null || libraryFilter(library)) {
+      rewriter.rewriteLibrary(library);
+    }
+  }
+  return program;
 }
 
 class RecursiveContinuationRewriter extends Transformer {
@@ -32,6 +38,10 @@ class RecursiveContinuationRewriter extends Transformer {
     return node.accept(this);
   }
 
+  Library rewriteLibrary(Library node) {
+    return node.accept(this);
+  }
+
   visitFunctionNode(FunctionNode node) {
     switch (node.asyncMarker) {
       case AsyncMarker.Sync: