[net] Cleanup filename_util and make it portable.

net/base/filename_util_internal.h

 // Copyright 2014 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.
 
 // Functions used internally by filename_util, filename_util_icu and
 // filename_util_unsafe.
 
 #ifndef NET_BASE_FILENAME_UTIL_INTERNAL_H_
 #define NET_BASE_FILENAME_UTIL_INTERNAL_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/strings/string16.h"
 
 class GURL;
 
 namespace net {
 
-typedef base::Callback<
-    void(base::FilePath::StringType* file_name, char replace_char)>
-    ReplaceIllegalCharactersCallback;
+extern const char kReplacement;
 
-void SanitizeGeneratedFileName(base::FilePath::StringType* filename,
-                               bool replace_trailing);
-
-bool IsShellIntegratedExtension(const base::FilePath::StringType& extension);
-
-bool IsReservedName(const base::FilePath::StringType& filename);
-
-void EnsureSafeExtension(const std::string& mime_type,
-                         bool ignore_extension,
-                         base::FilePath* file_name);
-
-bool FilePathToString16(const base::FilePath& path, base::string16* converted);
-
-// Similar to GetSuggestedFilename(), but takes callback to replace illegal
-// characters.
-base::string16 GetSuggestedFilenameImpl(
+// See documentation at filename_util_internal.cc
+std::string SelectUnsafeDownloadFilename(
     const GURL& url,
     const std::string& content_disposition,
     const std::string& referrer_charset,
     const std::string& suggested_name,
     const std::string& mime_type,
     const std::string& default_name,
-    ReplaceIllegalCharactersCallback replace_illegal_characters_callback);
+    ExtensionGenerationOption* extension_option);
 
-// Similar to GenerateFileName(), but takes callback to replace illegal
-// characters.
-base::FilePath GenerateFileNameImpl(
-    const GURL& url,
-    const std::string& content_disposition,
-    const std::string& referrer_charset,
-    const std::string& suggested_name,
-    const std::string& mime_type,
-    const std::string& default_name,
-    ReplaceIllegalCharactersCallback replace_illegal_characters_callback);
+// See documentation at filename_util_internal.cc
+void EnsureSafeFilenameInternal(const std::string& mime_type,
+                                ExtensionGenerationOption option,
+                                base::FilePath* filename);
 
 }  // namespace net
 
 #endif  // NET_BASE_FILENAME_UTIL_INTERNAL_H_