net: remove DNS certificate checking code.

chrome/browser/net/chrome_dns_cert_provenance_checker.h

-// Copyright (c) 2010 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.
-
-#ifndef CHROME_BROWSER_NET_CHROME_DNS_CERT_PROVENANCE_CHECKER
-#define CHROME_BROWSER_NET_CHROME_DNS_CERT_PROVENANCE_CHECKER
-#pragma once
-
-#include "net/socket/dns_cert_provenance_checker.h"
-
-#include <string>
-#include <vector>
-
-#include "base/string_piece.h"
-
-namespace net {
-class DnsRRResolver;
-}
-
-class ChromeURLRequestContext;
-
-// Factory function which creates ChromeDnsCertProvenanceChecker objects.
-//
-// WARNING: do not use this with anything other than the main
-// ChromeURLRequestContext. Eventually we'll want to have the other contexts
-// point to the main ChromeURLRequestContext, which then causes lifetime
-// ordering issues wrt ChromeURLRequestContexts, since we're using a raw
-// pointer, and we'll get shutdown ordering problems.
-net::DnsCertProvenanceChecker* CreateChromeDnsCertProvenanceChecker(
-    net::DnsRRResolver* dnsrr_resolver,
-    ChromeURLRequestContext* url_req_context);
-
-#endif  // CHROME_BROWSER_NET_CHROME_DNS_CERT_PROVENANCE_CHECKER