Introduce CryptAuthGCMManager, which handles GCM interactions for CryptAuth.

components/proximity_auth/cryptauth/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.
 
 source_set("cryptauth") {
   sources = [
     "base64url.cc",
     "base64url.h",
     "cryptauth_access_token_fetcher.h",
     "cryptauth_access_token_fetcher_impl.cc",
     "cryptauth_access_token_fetcher_impl.h",
     "cryptauth_api_call_flow.cc",
     "cryptauth_api_call_flow.h",
     "cryptauth_client.h",
     "cryptauth_client_impl.cc",
     "cryptauth_client_impl.h",
     "cryptauth_device_manager.cc",
     "cryptauth_device_manager.h",
     "cryptauth_enroller.h",
     "cryptauth_enroller_impl.cc",
     "cryptauth_enroller_impl.h",
     "cryptauth_enrollment_manager.cc",
     "cryptauth_enrollment_manager.h",
     "cryptauth_enrollment_utils.cc",
     "cryptauth_enrollment_utils.h",
+    "cryptauth_gcm_manager.cc",
+    "cryptauth_gcm_manager.h",
+    "cryptauth_gcm_manager_impl.cc",
+    "cryptauth_gcm_manager_impl.h",
     "pref_names.cc",
     "pref_names.h",
     "secure_message_delegate.cc",
     "secure_message_delegate.h",
     "sync_scheduler.cc",
     "sync_scheduler.h",
     "sync_scheduler_impl.cc",
     "sync_scheduler_impl.h",
   ]
 
   deps = [
     "//base",
     "//crypto",
+    "//components/gcm_driver",
     "//components/proximity_auth/logging",
     "//google_apis",
     "//net",
   ]
 
   public_deps = [
     "proto",
   ]
 }
 
@@ skipping 23 matching lines @@
 source_set("unit_tests") {
   testonly = true
   sources = [
     "base64url_unittest.cc",
     "cryptauth_access_token_fetcher_impl_unittest.cc",
     "cryptauth_api_call_flow_unittest.cc",
     "cryptauth_client_impl_unittest.cc",
     "cryptauth_device_manager_unittest.cc",
     "cryptauth_enroller_impl_unittest.cc",
     "cryptauth_enrollment_manager_unittest.cc",
+    "cryptauth_gcm_manager_impl_unittest.cc",
     "fake_secure_message_delegate_unittest.cc",
     "sync_scheduler_impl_unittest.cc",
   ]
 
   deps = [
     ":cryptauth",
     ":test_support",
     "//base:prefs_test_support",
     "//base/test:test_support",
+    "//components/gcm_driver:test_support",
     "//google_apis:test_support",
     "//net:test_support",
     "//testing/gtest",
   ]
 }