Add cloud_devices and json_schema to GN build.

components/cloud_devices/common/BUILD.gn

Index: components/cloud_devices/common/BUILD.gn
diff --git a/components/cloud_devices/common/BUILD.gn b/components/cloud_devices/common/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..800146f8bfb17c83352db365c43c98c23e8dcb8d
--- /dev/null
+++ b/components/cloud_devices/common/BUILD.gn
@@ -0,0 +1,25 @@
+# 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("common") {
+  output_name = "cloud_devices_common"
+  sources = [
+    "cloud_device_description.cc",
+    "cloud_device_description.h",
+    "cloud_device_description_consts.cc",
+    "cloud_device_description_consts.h",
+    "cloud_devices_switches.cc",
+    "cloud_devices_switches.h",
+    "cloud_devices_urls.cc",
+    "cloud_devices_urls.h",
+    "description_items.h",
+    "description_items_inl.h",
+    "printer_description.cc",
+    "printer_description.h",
+  ]
+  deps = [
+    "//base",
+    "//net",
+  ]
+}