GN build improvements.

tools/gn/secondary/third_party/wtl/BUILD.gn

Index: tools/gn/secondary/third_party/wtl/BUILD.gn
diff --git a/tools/gn/secondary/third_party/wtl/BUILD.gn b/tools/gn/secondary/third_party/wtl/BUILD.gn
deleted file mode 100644
index 7ebe9d99d2092b1c5e952d8e51ad09d69c447910..0000000000000000000000000000000000000000
--- a/tools/gn/secondary/third_party/wtl/BUILD.gn
+++ /dev/null
@@ -1,14 +0,0 @@
-# Copyright (c) 2013 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-config("wtl_includes") {
-  include_dirs = [ "include" ]
-}
-
-# WTL is only header files so we use a "group" target type which doesn't
-# actually generate anything linkable, and inject the required config for
-# making the include directories work.
-group("wtl") {
-  all_dependent_configs = ":wtl_includes"
-}