Forward dependent configs from groups properly in GN.

tools/gn/target.h

Index: tools/gn/target.h
diff --git a/tools/gn/target.h b/tools/gn/target.h
index 6b8eb99e186bbea2ec042f458c3612faa3956956..6f3965b492d3e60b705de7d040e08d6262fdd18a 100644
--- a/tools/gn/target.h
+++ b/tools/gn/target.h
@@ -150,6 +150,9 @@ class Target : public Item {
   // dependencies have been resolved.
   void PullDependentTargetInfo(std::set<const Config*>* unique_configs);
 
+  // Pulls dependent configs that need forwarding.
+  void PullForwardedDependentConfigs();
+
   OutputType output_type_;
   std::string output_name_;
   std::string output_extension_;