Add GN function get_label_info

tools/gn/loader.cc

Index: tools/gn/loader.cc
diff --git a/tools/gn/loader.cc b/tools/gn/loader.cc
index 885670ab80572bd1d1d5d82baec4265cc1c3c631..4cca2ce71b2805f5eeb9004a55cba0a0630c2853 100644
--- a/tools/gn/loader.cc
+++ b/tools/gn/loader.cc
@@ -19,20 +19,6 @@
 #include "tools/gn/source_file.h"
 #include "tools/gn/trace.h"
 
-namespace {
-
-std::string GetOutputSubdirName(const Label& toolchain_label, bool is_default) {
-  // The default toolchain has no subdir.
-  if (is_default)
-    return std::string();
-
-  // For now just assume the toolchain name is always a valid dir name. We may
-  // want to clean up the in the future.
-  return toolchain_label.name();
-}
-
-}  // namespace
-
 // Identifies one time a file is loaded in a given toolchain so we don't load
 // it more than once.
 struct LoaderImpl::LoadID {