Await it!

runtime/vm/ast_transformer.h

Index: runtime/vm/ast_transformer.h
diff --git a/runtime/vm/ast_transformer.h b/runtime/vm/ast_transformer.h
index 18faf7b3bd5cde8a5f93f28c19499bb650496476..6fbd82bec598676dba00701d02493e7082fdbf26 100644
--- a/runtime/vm/ast_transformer.h
+++ b/runtime/vm/ast_transformer.h
@@ -46,7 +46,13 @@ class AwaitTransformer : public AstNodeVisitor {
       temp_cnt_(0),
       library_(library),
       parsed_function_(parsed_function),
-      isolate_(Isolate::Current()) {}
+      isolate_(Isolate::Current()) {
+    // We later on save the continuation context and modify the jump counter
+    // from within the preamble context (in the FlowGraphBuilder). Look up the
+    // needed variables to get their corresponding aliases.
+    preamble->scope()->LookupVariable(Symbols::AwaitContextVar(), false);
+    preamble->scope()->LookupVariable(Symbols::AwaitJumpVar(), false);
+  }
 
 #define DECLARE_VISIT(BaseName)                                                \
   virtual void Visit##BaseName##Node(BaseName##Node* node);