GN: Prefer toplevel targets for phony names.

tools/gn/ninja_build_writer.h

Index: tools/gn/ninja_build_writer.h
diff --git a/tools/gn/ninja_build_writer.h b/tools/gn/ninja_build_writer.h
index 0d5b40eef70fe60d330cd91203e36cbcd4b172f0..e94f93de24e60ce5ec215a9ec15e40c42b9b32ba 100644
--- a/tools/gn/ninja_build_writer.h
+++ b/tools/gn/ninja_build_writer.h
@@ -46,12 +46,7 @@ class NinjaBuildWriter {
   void WriteSubninjas();
   bool WritePhonyAndAllRules(Err* err);
 
-  // Writes a phony rule for the given target with the given name. Adds the new
-  // name to the given set. If the name is already in the set, does nothing.
-  void WritePhonyRule(const Target* target,
-                      const OutputFile& target_file,
-                      const std::string& phony_name,
-                      std::set<std::string>* written_rules);
+  void WritePhonyRule(const Target* target, const std::string& phony_name);
 
   const BuildSettings* build_settings_;
   std::vector<const Settings*> all_settings_;