Track merged nudge sources

sync/sessions/sync_session.h

 // Copyright (c) 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.
 
 // A class representing an attempt to synchronize the local syncable data
 // store with a sync server. A SyncSession instance is passed as a stateful
 // bundle to and from various SyncerCommands with the goal of converging the
 // client view of data with that of the server. The commands twiddle with
 // session status in response to events and hiccups along the way, set and
 // query session progress with regards to conflict resolution and applying
@@ skipping 147 matching lines @@
   // assignments. This way, the scope of these actions is explicit, they can't
   // be overridden, and assigning is always accompanied by unassigning.
   friend class ScopedSetSessionWriteTransaction;
 
   // The context for this session, guaranteed to outlive |this|.
   SyncSessionContext* const context_;
 
   // The source for initiating this sync session.
   SyncSourceInfo source_;
 
+  // A list of sources for sessions that have been merged with this one.
+  // Currently used only for logging.
+  std::vector<SyncSourceInfo> debug_info_sources_list_;
+
   // Information about extensions activity since the last successful commit.
   ExtensionsActivityMonitor::Records extensions_activity_;
 
   // Used to allow various steps to share a transaction. Can be NULL.
   syncable::WriteTransaction* write_transaction_;
 
   // The delegate for this session, must never be NULL.
   Delegate* const delegate_;
 
   // Our controller for various status and error counters.
@@ skipping 30 matching lines @@
 
  private:
   SyncSession* session_;
   DISALLOW_COPY_AND_ASSIGN(ScopedSetSessionWriteTransaction);
 };
 
 }  // namespace sessions
 }  // namespace syncer
 
 #endif  // SYNC_SESSIONS_SYNC_SESSION_H_