Move some component's GN build files to main tree.

tools/gn/secondary/components/language_usage_metrics/BUILD.gn

Index: tools/gn/secondary/components/language_usage_metrics/BUILD.gn
diff --git a/tools/gn/secondary/components/language_usage_metrics/BUILD.gn b/tools/gn/secondary/components/language_usage_metrics/BUILD.gn
deleted file mode 100644
index a3e26be15e8575cc271283c7c95ea6baf1f3cd7c..0000000000000000000000000000000000000000
--- a/tools/gn/secondary/components/language_usage_metrics/BUILD.gn
+++ /dev/null
@@ -1,14 +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.
-
-static_library("language_usage_metrics") {
-  sources = [
-    "language_usage_metrics.cc",
-    "language_usage_metrics.h",
-  ]
-
-  deps = [
-    "//base",
-  ]
-}