[modules] Support exporting a local variable under multiple export names.

src/ast/modules.h

Index: src/ast/modules.h
diff --git a/src/ast/modules.h b/src/ast/modules.h
index 3e956c1e7cb4c70d97f6005e583e5487232e58da..e9a35646cdedec4806908342a4949af8ec68174b 100644
--- a/src/ast/modules.h
+++ b/src/ast/modules.h
@@ -155,6 +155,11 @@ class ModuleDescriptor : public ZoneObject {
     special_imports_.Add(entry, zone);
   }
 
+  Handle<FixedArray> SerializeRegularExports(Isolate* isolate,
+                                             Zone* zone) const;
+  void DeserializeRegularExports(Isolate* isolate, AstValueFactory* avfactory,
+                                 Handle<FixedArray> data);
+
  private:
   // TODO(neis): Use STL datastructure instead of ZoneList?
   ZoneMap<const AstRawString*, int> module_requests_;