[net] Remove logic for fixing up Gzip encoding type for downloads.

net/base/filename_util_unsafe.cc

-// 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.
-
-#include "net/base/filename_util_unsafe.h"
-
-#include "base/bind.h"
-#include "base/strings/string_util.h"
-#include "net/base/filename_util_internal.h"
-
-namespace {
-
-// Local ICU-independent implementation of filename sanitizing functions defined
-// in base/i18n/file_util_icu.h. Does not require ICU because on POSIX systems
-// all international characters are considered legal, so only control and
-// special characters have to be replaced.
-const base::FilePath::CharType illegal_characters[] =
-    FILE_PATH_LITERAL("\"*/:<>?\\\\|\001\002\003\004\005\006\007\010\011\012")
-    FILE_PATH_LITERAL("\013\014\015\016\017\020\021\022\023\024\025\025\027");
-
-void ReplaceIllegalCharactersInPath(base::FilePath::StringType* file_name,
-                                    char replace_char) {
-  base::ReplaceChars(*file_name,
-                     illegal_characters,
-                     base::FilePath::StringType(1, replace_char),
-                     file_name);
-}
-
-}  // namespace
-
-namespace net {
-
-base::FilePath::StringType GenerateFileExtensionUnsafe(
-    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_file_name) {
-  base::FilePath filepath =
-      GenerateFileNameImpl(url,
-                           content_disposition,
-                           referrer_charset,
-                           suggested_name,
-                           mime_type,
-                           default_file_name,
-                           base::Bind(&ReplaceIllegalCharactersInPath));
-  return filepath.Extension();
-}
-
-}  // namespace net