Move some of IOThread's command line logic to network_session_configurator.

components/network_session_configurator/common/BUILD.gn

Index: components/network_session_configurator/common/BUILD.gn
diff --git a/components/network_session_configurator/common/BUILD.gn b/components/network_session_configurator/common/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..60bd2ea64ccd99e486345bef1af7893cc457b8b4
--- /dev/null
+++ b/components/network_session_configurator/common/BUILD.gn
@@ -0,0 +1,15 @@
+# Copyright 2017 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("common") {
+  sources = [
+    "network_switch_list.h",
+    "network_switches.cc",
+    "network_switches.h",
+  ]
+
+  public_deps = [
+    "//base",
+  ]
+}