Improve GN handling of directory templates.

tools/gn/ninja_target_writer.h

Index: tools/gn/ninja_target_writer.h
diff --git a/tools/gn/ninja_target_writer.h b/tools/gn/ninja_target_writer.h
index 51e3ba160463f8d75ee0cf3567eb8722eee22fd5..6cd0a0ad8a9113ab0bc9d24b61563f4bef59e7e5 100644
--- a/tools/gn/ninja_target_writer.h
+++ b/tools/gn/ninja_target_writer.h
@@ -38,12 +38,6 @@ class NinjaTargetWriter {
   std::string WriteInputDepsStampAndGetDep(
       const std::vector<const Target*>& extra_hard_deps) const;
 
-  // Returns the FileTemplate constructed from the outputs variable. This is
-  // like FileTemplate::GetForTargetOutputs except this additionally trims the
-  // build directory from the front so we can just write the names without
-  // further processing.
-  FileTemplate GetOutputTemplate() const;
-
   const Settings* settings_;  // Non-owning.
   const Target* target_;  // Non-owning.
   const Toolchain* toolchain_;  // Non-owning.