[net] Cleanup filename_util and make it portable.

net/base/filename_util.cc

Index: net/base/filename_util.cc
diff --git a/net/base/filename_util.cc b/net/base/filename_util.cc
index 6573c2261610593dd145b071f4ad24bf54082c07..6f659c9a4662fe6c1afe0f7d4f2a8004815f056a 100644
--- a/net/base/filename_util.cc
+++ b/net/base/filename_util.cc
@@ -138,26 +138,4 @@ bool FileURLToFilePath(const GURL& url, base::FilePath* file_path) {
   return !file_path_str.empty();
 }
 
-void GenerateSafeFileName(const std::string& mime_type,
-                          bool ignore_extension,
-                          base::FilePath* file_path) {
-  // Make sure we get the right file extension
-  EnsureSafeExtension(mime_type, ignore_extension, file_path);
-
-#if defined(OS_WIN)
-  // Prepend "_" to the file name if it's a reserved name
-  base::FilePath::StringType leaf_name = file_path->BaseName().value();
-  DCHECK(!leaf_name.empty());
-  if (IsReservedName(leaf_name)) {
-    leaf_name = base::FilePath::StringType(FILE_PATH_LITERAL("_")) + leaf_name;
-    *file_path = file_path->DirName();
-    if (file_path->value() == base::FilePath::kCurrentDirectory) {
-      *file_path = base::FilePath(leaf_name);
-    } else {
-      *file_path = file_path->Append(leaf_name);
-    }
-  }
-#endif
-}
-
 }  // namespace net