Add support for GCM subtypes to desktop Instance ID implementation

components/gcm_driver/instance_id/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.
 
 # GYP version: components/gcm_driver.gypi:instance_id_driver
 static_library("instance_id") {
   sources = [
     "android/component_jni_registrar.cc",
     "android/component_jni_registrar.h",
     "instance_id.cc",
@@ skipping 52 matching lines @@
   testonly = true
   sources = [
     "instance_id_driver_unittest.cc",
   ]
 
   deps = [
     ":instance_id",
     ":test_support",
     "//base",
     "//google_apis/gcm",
+    "//net:test_support",
     "//testing/gtest",
   ]
 }