Remove unnecessary attempts at memory cleaning

net/base/zap.cc

-// 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.
-
-#include "net/base/zap.h"
-
-#include <string.h>
-
-namespace net {
-
-void ZapBuf(void* buf, size_t buf_len) {
-  memset(buf, 0x0, buf_len);
-}
-
-void ZapString(std::string* s) {
-  if (!s->empty())
-    ZapBuf(&(*s)[0], s->length() * sizeof(char));
-}
-
-void ZapString(base::string16* s) {
-  if (!s->empty())
-    ZapBuf(&(*s)[0], s->length() * sizeof(base::char16));
-}
-
-}  // namespace net