[Coverity] Fixed call by value to by reference

base/file_util_proxy.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 BASE_FILE_UTIL_PROXY_H_
 #define BASE_FILE_UTIL_PROXY_H_
 
 #include <vector>
 
 #include "base/base_export.h"
@@ skipping 23 matching lines @@
   // This callback is used by methods that report only an error code.  It is
   // valid to pass a null callback to any function that takes a StatusCallback,
   // in which case the operation will complete silently.
   typedef Callback<void(PlatformFileError)> StatusCallback;
 
   typedef Callback<void(PlatformFileError,
                         PassPlatformFile,
                         bool /* created */)> CreateOrOpenCallback;
   typedef Callback<void(PlatformFileError,
                         PassPlatformFile,
-                        FilePath)> CreateTemporaryCallback;
+                        const FilePath&)> CreateTemporaryCallback;
   typedef Callback<void(PlatformFileError,
                         const PlatformFileInfo&
                        )> GetFileInfoCallback;
   typedef Callback<void(PlatformFileError,
                         const char* /* data */,
                         int /* bytes read */)> ReadCallback;
   typedef Callback<void(PlatformFileError,
                         int /* bytes written */)> WriteCallback;
 
   typedef Callback<PlatformFileError(PlatformFile*, bool*)> CreateOrOpenTask;
@@ skipping 132 matching lines @@
       PlatformFile,
       const StatusCallback& callback);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(FileUtilProxy);
 };
 
 }  // namespace base
 
 #endif  // BASE_FILE_UTIL_PROXY_H_