[Sync] Introduce SyncedSessionWindow type.

components/sessions/core/session_types.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_SESSIONS_CORE_SESSION_TYPES_H_
 #define COMPONENTS_SESSIONS_CORE_SESSION_TYPES_H_
 
 #include <algorithm>
 #include <memory>
 #include <string>
@@ skipping 85 matching lines @@
   // Timestamp for when this tab was last activated. As these use TimeTicks,
   // they should not be compared with one another, unless it's within the same
   // chrome session.
   base::TimeTicks last_active_time;
 
   std::vector<sessions::SerializedNavigationEntry> navigations;
 
   // For reassociating sessionStorage.
   std::string session_storage_persistent_id;
 
-  // Ids of the currently assigned variations which should be sent to sync.
-  std::vector<variations::VariationID> variation_ids;
-
  private:
   DISALLOW_COPY_AND_ASSIGN(SessionTab);
 };
 
 // SessionWindow -------------------------------------------------------------
 
 // Describes a saved window.
 struct SESSIONS_EXPORT SessionWindow {
   SessionWindow();
   ~SessionWindow();
 
   // Possible window types which can be stored here. Note that these values will
   // be written out to disc via session commands.
   enum WindowType {
     TYPE_TABBED = 0,
     TYPE_POPUP = 1
   };
 
-  // Convert this object into its sync protocol buffer equivalent. Note that
-  // not all fields are synced here, because they don't all make sense or
-  // translate when restoring a SessionWindow on another device.
-  sync_pb::SessionWindow ToSyncData() const;
-
   // Identifier of the window.
   SessionID window_id;
 
   // Bounds of the window.
   gfx::Rect bounds;
 
   // The workspace in which the window resides.
   std::string workspace;
 
   // Index of the selected tab in tabs; -1 if no tab is selected. After restore
@@ skipping 26 matching lines @@
 
   std::string app_name;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SessionWindow);
 };
 
 }  // namespace sessions
 
 #endif  // COMPONENTS_SESSIONS_CORE_SESSION_TYPES_H_