[Sync] Made some sync session member functions const

chrome/browser/sync/engine/download_updates_command.h

 // Copyright (c) 2011 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 CHROME_BROWSER_SYNC_ENGINE_DOWNLOAD_UPDATES_COMMAND_H_
 #define CHROME_BROWSER_SYNC_ENGINE_DOWNLOAD_UPDATES_COMMAND_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 28 matching lines @@
 // changes_remaining == 0 in the GetUpdates response), or until an error
 // is encountered.
 class DownloadUpdatesCommand : public SyncerCommand {
  public:
   DownloadUpdatesCommand();
   virtual ~DownloadUpdatesCommand();
 
   // SyncerCommand implementation.
   virtual void ExecuteImpl(sessions::SyncSession* session) OVERRIDE;
 
-  void SetRequestedTypes(const syncable::ModelTypeBitSet& target_datatypes,
-                         sync_pb::EntitySpecifics* filter_protobuf);
-
  private:
   FRIEND_TEST_ALL_PREFIXES(DownloadUpdatesCommandTest, VerifyAppendDebugInfo);
   void AppendClientDebugInfoIfNeeded(sessions::SyncSession* session,
       sync_pb::DebugInfo* debug_info);
   DISALLOW_COPY_AND_ASSIGN(DownloadUpdatesCommand);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_DOWNLOAD_UPDATES_COMMAND_H_