Address more TODO(GYP) in the GN build.

chrome/tools/BUILD.gn

Index: chrome/tools/BUILD.gn
diff --git a/chrome/tools/BUILD.gn b/chrome/tools/BUILD.gn
deleted file mode 100644
index af932bd96be9f42a6d8f548ad28a38a26b042153..0000000000000000000000000000000000000000
--- a/chrome/tools/BUILD.gn
+++ /dev/null
@@ -1,19 +0,0 @@
-# Copyright 2014 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.
-
-# This target just provides references to the Chrome tools to bring them into
-# the build.
-group("tools") {
-  testonly = true
-  if (is_linux && !is_chromeos) {
-    # TODO(GYP): Figure out which of these work and are needed on other platforms.
-    deps = [
-      "//chrome/tools/service_discovery_sniffer",
-    ]
-  } else if (is_mac) {
-    deps = [
-      "//chrome/tools/mac_helpers",
-    ]
-  }
-}