Remove support for the keygen tag

ios/chrome/browser/browser_state/chrome_browser_state_io_data.cc

 // Copyright 2015 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 "ios/chrome/browser/browser_state/chrome_browser_state_io_data.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <utility>
@@ skipping 26 matching lines @@
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #include "ios/chrome/browser/content_settings/cookie_settings_factory.h"
 #include "ios/chrome/browser/content_settings/host_content_settings_map_factory.h"
 #include "ios/chrome/browser/ios_chrome_io_thread.h"
 #include "ios/chrome/browser/net/ios_chrome_http_user_agent_settings.h"
 #include "ios/chrome/browser/net/ios_chrome_network_delegate.h"
 #include "ios/chrome/browser/net/ios_chrome_url_request_context_getter.h"
 #include "ios/chrome/browser/net/proxy_service_factory.h"
 #include "ios/web/public/web_thread.h"
-#include "net/base/keygen_handler.h"
 #include "net/cert/cert_verifier.h"
 #include "net/cert/multi_log_ct_verifier.h"
 #include "net/cookies/canonical_cookie.h"
 #include "net/http/http_network_session.h"
 #include "net/http/http_transaction_factory.h"
 #include "net/http/http_util.h"
 #include "net/http/transport_security_persister.h"
 #include "net/nqe/network_quality_estimator.h"
 #include "net/proxy/proxy_config_service_fixed.h"
 #include "net/proxy/proxy_script_fetcher_impl.h"
@@ skipping 426 matching lines @@
   return std::unique_ptr<net::HttpCache>(
       new net::HttpCache(session, std::move(main_backend), true));
 }
 
 std::unique_ptr<net::HttpCache> ChromeBrowserStateIOData::CreateHttpFactory(
     net::HttpNetworkSession* shared_session,
     std::unique_ptr<net::HttpCache::BackendFactory> backend) const {
   return std::unique_ptr<net::HttpCache>(
       new net::HttpCache(shared_session, std::move(backend), true));
 }