Add MDP for TabRestorer.

components/sessions/core/serialized_navigation_entry.h

 // Copyright 2013 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_SERIALIZED_NAVIGATION_ENTRY_H_
 #define COMPONENTS_SESSIONS_CORE_SERIALIZED_NAVIGATION_ENTRY_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 110 matching lines @@
   void set_content_pack_categories(
       const std::set<std::string>& content_pack_categories) {
     content_pack_categories_ = content_pack_categories;
   }
   const std::vector<GURL>& redirect_chain() const { return redirect_chain_; }
 
   const std::map<std::string, std::string>& extended_info_map() const {
     return extended_info_map_;
   }
 
+  size_t EstimateMemoryUsage() const;
+
  private:
   friend class ContentSerializedNavigationBuilder;
   friend class ContentSerializedNavigationDriver;
   friend class SerializedNavigationEntryTestHelper;
   friend class IOSSerializedNavigationBuilder;
   friend class IOSSerializedNavigationDriver;
 
   // Index in the NavigationController.
   int index_;
 
@@ skipping 22 matching lines @@
   std::set<std::string> content_pack_categories_;
 
   // Provides storage for arbitrary key/value pairs used by features. This
   // data is not synced.
   std::map<std::string, std::string> extended_info_map_;
 };
 
 }  // namespace sessions
 
 #endif  // COMPONENTS_SESSIONS_CORE_SERIALIZED_NAVIGATION_ENTRY_H_