[net] Cleanup filename_util and make it portable.

chrome/browser/download/download_target_determiner.cc

 // Copyright 2013 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 "chrome/browser/download/download_target_determiner.h"
 
 #include "base/prefs/pref_service.h"
 #include "base/rand_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/time/time.h"
@@ skipping 251 matching lines @@
   if (!suggested_path.empty()) {
     // If an extension overrides the filename, then the target directory will be
     // forced to download_prefs_->DownloadPath() since extensions cannot place
     // downloaded files anywhere except there. This prevents subdirectories from
     // accumulating: if an extension is allowed to say that a file should go in
     // last_download_path/music/foo.mp3, then last_download_path will accumulate
     // the subdirectory /music/ so that the next download may end up in
     // Downloads/music/music/music/bar.mp3.
     base::FilePath new_path(download_prefs_->DownloadPath().Append(
         suggested_path).NormalizePathSeparators());
-    // Do not pass a mime type to GenerateSafeFileName so that it does not force
-    // the filename to have an extension if the (Chrome) extension does not
-    // suggest it.
-    net::GenerateSafeFileName(std::string(), false, &new_path);
+    net::EnsureSafePortableFileName(
+        std::string(), net::EXTENSION_OPTION_KEEP_EXISTING, &new_path);
     virtual_path_ = new_path;
     create_target_directory_ = true;
   }
   // An extension may set conflictAction without setting filename.
   if (conflict_action != DownloadPathReservationTracker::UNIQUIFY)
     conflict_action_ = conflict_action;
 
   DoLoop();
 }
 
@@ skipping 600 matching lines @@
     const base::FilePath& suggested_path) {
   return base::FilePath(suggested_path.value() + kCrdownloadSuffix);
 }
 
 #if defined(OS_WIN)
 // static
 bool DownloadTargetDeterminer::IsAdobeReaderUpToDate() {
   return g_is_adobe_reader_up_to_date_;
 }
 #endif