[Sync] Fix sync lint errors/includes, update presubmit.

components/sync/engine_impl/loopback_server/loopback_server.h

 // Copyright 2016 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_SYNC_ENGINE_IMPL_LOOPBACK_SERVER_LOOPBACK_SERVER_H_
 #define COMPONENTS_SYNC_ENGINE_IMPL_LOOPBACK_SERVER_LOOPBACK_SERVER_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/threading/thread_checker.h"
 #include "base/values.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/engine_impl/loopback_server/loopback_server_entity.h"
 #include "components/sync/engine_impl/net/server_connection_manager.h"
 #include "components/sync/protocol/loopback_server.pb.h"
 #include "components/sync/protocol/sync.pb.h"
 
 namespace syncer {
 
 // A loopback version of the Sync server used for local profile serialization.
 class LoopbackServer {
  public:
-  LoopbackServer(const base::FilePath& persistent_file);
+  explicit LoopbackServer(const base::FilePath& persistent_file);
   virtual ~LoopbackServer();
 
   // Handles a /command POST (with the given |request|) to the server. Three
   // output arguments, |server_status|, |response_code|, and |response|, are
   // used to pass data back to the caller. The command has failed if the value
   // pointed to by |error_code| is nonzero.
   void HandleCommand(const std::string& request,
                      HttpResponse::ServerConnectionCode* server_status,
                      int64_t* response_code,
                      std::string* response);
@@ skipping 85 matching lines @@
   // The file used to store the local sync data.
   base::FilePath persistent_file_;
 
   // Used to verify that LoopbackServer is only used from one thread.
   base::ThreadChecker thread_checker_;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_IMPL_LOOPBACK_SERVER_LOOPBACK_SERVER_H_