components: Add GN Build files for component_updater and user_manager.

components/component_updater/BUILD.gn

Index: components/component_updater/BUILD.gn
diff --git a/components/component_updater/BUILD.gn b/components/component_updater/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..500349b57cfc423212d4b3a3eecbf35dd4d98b55
--- /dev/null
+++ b/components/component_updater/BUILD.gn
@@ -0,0 +1,18 @@
+# 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.
+
+source_set("component_updater") {
+  sources = [
+    "component_updater_paths.cc",
+    "component_updater_paths.h",
+    "component_updater_switches.cc",
+    "component_updater_switches.h",
+    "pref_names.cc",
+    "pref_names.h",
+  ]
+
+  deps = [
+    "//base",
+  ]
+}