[modules] Introduce new VariableLocation for module imports/exports.

src/ast/modules.h

Index: src/ast/modules.h
diff --git a/src/ast/modules.h b/src/ast/modules.h
index c672f2494917b60bbc310638c7786024410642a5..5c418fc3019ffb93914f43c231d861b0dc243a53 100644
--- a/src/ast/modules.h
+++ b/src/ast/modules.h
@@ -67,8 +67,6 @@ class ModuleDescriptor : public ZoneObject {
       Scope* module_scope, PendingCompilationErrorHandler* error_handler,
       Zone* zone) const;
 
-
- private:
   struct ModuleEntry : public ZoneObject {
     const Scanner::Location location;
     const AstRawString* export_name;
@@ -84,6 +82,10 @@ class ModuleDescriptor : public ZoneObject {
           module_request(nullptr) {}
   };
 
+  const ZoneList<const ModuleEntry*>& exports() { return exports_; }
+  const ZoneList<const ModuleEntry*>& imports() { return imports_; }
+
+ private:
   ZoneList<const ModuleEntry*> exports_;
   ZoneList<const ModuleEntry*> imports_;
 };