Add components and CLD to GN build.

components/captive_portal/BUILD.gn

+# 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.
+
+component("captive_portal") {
+  sources = [
+    "captive_portal_detector.cc",
+    "captive_portal_detector.h",
+    "captive_portal_types.cc",
+    "captive_portal_types.h",
+    "captive_portal_export.h",
+  ]
+
+  defines = [ "CAPTIVE_PORTAL_IMPLEMENTATION" ]
+
+  deps = [
+    "//base",
+    "//net",
+    "//url",
+  ]
+}
+
+static_library("test_support") {
+  sources = [
+    "captive_portal_testing_utils.cc",
+    "captive_portal_testing_utils.h",
+  ]
+
+  deps = [
+    ":captive_portal",
+    "//base",
+    "//net",
+    "//url",
+  ]
+}