[sync] Componentize sync: Part 6: Add more SYNC_EXPORTs to files in src/sync/

sync/sessions/debug_info_getter.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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 SYNC_SESSIONS_DEBUG_INFO_GETTER_H_
 #define SYNC_SESSIONS_DEBUG_INFO_GETTER_H_
 
+#include "sync/base/sync_export.h"
 #include "sync/protocol/sync.pb.h"
 
 namespace syncer {
 namespace sessions {
 
 // This is the interface that needs to be implemented by the event listener
 // to communicate the debug info data to the syncer.
-class DebugInfoGetter {
+class SYNC_EXPORT_PRIVATE DebugInfoGetter {
  public:
   // Gets the client debug info and clears the state so the same data is not
   // sent again.
   virtual void GetAndClearDebugInfo(sync_pb::DebugInfo* debug_info) = 0;
   virtual ~DebugInfoGetter() {}
 };
 
 }  // namespace sessions
 }  // namespace syncer
 
 #endif  // SYNC_SESSIONS_DEBUG_INFO_GETTER_H_