components: Cleanup class/struct fwd declarations

components/ntp_snippets/remote/ntp_snippets_test_utils.h

 // Copyright 2016 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.
 
 #ifndef COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_TEST_UTILS_H_
 #define COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_TEST_UTILS_H_
 
 #include <memory>
 
 #include "components/sync/driver/fake_sync_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 class AccountTrackerService;
 class FakeSigninManagerBase;
-class MockSyncService;
 class TestingPrefServiceSimple;
 class TestSigninClient;
 
 namespace ntp_snippets {
 namespace test {
 
 class FakeSyncService : public syncer::FakeSyncService {
  public:
   FakeSyncService();
   ~FakeSyncService() override;
@@ skipping 31 matching lines @@
   std::unique_ptr<FakeSyncService> fake_sync_service_;
   std::unique_ptr<TestingPrefServiceSimple> pref_service_;
   std::unique_ptr<TestSigninClient> signin_client_;
   std::unique_ptr<AccountTrackerService> account_tracker_;
 };
 
 }  // namespace test
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_REMOTE_NTP_SNIPPETS_TEST_UTILS_H_