[GCM] Exposing persistence of account mappings in GCM Driver

components/gcm_driver/fake_gcm_driver.cc

 // 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.
 
 #include "components/gcm_driver/fake_gcm_driver.h"
 
 namespace gcm {
 
 FakeGCMDriver::FakeGCMDriver() {
 }
@@ skipping 52 matching lines @@
 }
 
 void FakeGCMDriver::UnregisterImpl(const std::string& app_id) {
 }
 
 void FakeGCMDriver::SendImpl(const std::string& app_id,
                              const std::string& receiver_id,
                              const GCMClient::OutgoingMessage& message) {
 }
 
+void FakeGCMDriver::UpdateAccountMapping(
+    const AccountMapping& account_mapping) {
+}
+
+void FakeGCMDriver::RemoveAccountMapping(const std::string& account_id) {
+}
+
 }  // namespace gcm