components: Cleanup class/struct fwd declarations

components/sync_sessions/sessions_sync_manager.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_SESSIONS_SESSIONS_SYNC_MANAGER_H_
 #define COMPONENTS_SYNC_SESSIONS_SESSIONS_SYNC_MANAGER_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 25 matching lines @@
 class LocalDeviceInfoProvider;
 class SyncErrorFactory;
 class SyncPrefs;
 }  // namespace syncer
 
 namespace sync_pb {
 class SessionHeader;
 class SessionSpecifics;
 class SessionTab;
 class SessionWindow;
-class TabNavigation;
 }  // namespace sync_pb
 
 namespace extensions {
 class ExtensionSessionsTest;
 }  // namespace extensions
 
 namespace sync_sessions {
 
 class SyncedTabDelegate;
 class SyncedWindowDelegatesGetter;
@@ skipping 319 matching lines @@
 
   // Callback to inform sync that a sync data refresh is requested.
   base::Closure datatype_refresh_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(SessionsSyncManager);
 };
 
 }  // namespace sync_sessions
 
 #endif  // COMPONENTS_SYNC_SESSIONS_SESSIONS_SYNC_MANAGER_H_