[Sync] Introduce SyncedSessionWindow type.

components/sync_sessions/synced_session_tracker.h

 // Copyright 2012 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_SYNCED_SESSION_TRACKER_H_
 #define COMPONENTS_SYNC_SESSIONS_SYNCED_SESSION_TRACKER_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 201 matching lines @@
   SyncSessionsClient* const sessions_client_;
 
   // The mapping of tab/window to their SessionTab/SessionWindow objects.
   // The SessionTab/SessionWindow objects referred to may be owned either by the
   // session in the |synced_session_map_| or be temporarily unmapped and live in
   // the |unmapped_tabs_|/|unmapped_windows_| collections.
   //
   // Map: session tag -> (tab/window -> SessionTab*/SessionWindow*)
   std::map<std::string, std::map<SessionID::id_type, sessions::SessionTab*>>
       synced_tab_map_;
-  std::map<std::string, std::map<SessionID::id_type, sessions::SessionWindow*>>
+  std::map<std::string, std::map<SessionID::id_type, SyncedSessionWindow*>>
       synced_window_map_;
 
   // The collection that owns the SyncedSessions, and transitively, all of the
   // windows and tabs they contain.
   //
   // Map: session tag -> owned SyncedSession
   std::map<std::string, std::unique_ptr<SyncedSession>> synced_session_map_;
 
   // The collection of tabs/windows not owned by a SyncedSession. This is the
   // case either because 1. (in the case of tabs) they were newly created by
   // GetTab() and not yet added to a session, or 2. they were removed from their
   // owning session by a call to ResetSessionTracking() and not yet added back.
   //
   // Map: session tag -> (tab/window id -> owned SessionTab/SessionWindow)
   std::map<std::string,
            std::map<SessionID::id_type, std::unique_ptr<sessions::SessionTab>>>
       unmapped_tabs_;
-  std::map<
-      std::string,
-      std::map<SessionID::id_type, std::unique_ptr<sessions::SessionWindow>>>
+  std::map<std::string,
+           std::map<SessionID::id_type, std::unique_ptr<SyncedSessionWindow>>>
       unmapped_windows_;
 
   // The tag for this machine's local session, so we can distinguish the foreign
   // sessions.
   std::string local_session_tag_;
 
   // Pool of used/available sync nodes associated with local tabs.
   TabNodePool local_tab_pool_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncedSessionTracker);
 };
 
 }  // namespace sync_sessions
 
 #endif  // COMPONENTS_SYNC_SESSIONS_SYNCED_SESSION_TRACKER_H_