Stop using CertStore which is not compatible with PlzNavigate.

ios/chrome/browser/ssl/ios_chrome_security_state_model_client.mm

 // Copyright 2016 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/ssl/ios_chrome_security_state_model_client.h"
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
-#include "ios/web/public/cert_store.h"
 #include "ios/web/public/navigation_item.h"
 #import "ios/web/public/navigation_manager.h"
 #import "ios/web/public/origin_util.h"
 #include "ios/web/public/security_style.h"
 #include "ios/web/public/ssl_status.h"
 #include "ios/web/public/web_state/web_state.h"
 #include "net/cert/x509_certificate.h"
 
 DEFINE_WEB_STATE_USER_DATA_KEY(IOSChromeSecurityStateModelClient);
 
@@ skipping 37 matching lines @@
 
 const security_state::SecurityStateModel::SecurityInfo&
 IOSChromeSecurityStateModelClient::GetSecurityInfo() const {
   return security_state_model_->GetSecurityInfo();
 }
 
 bool IOSChromeSecurityStateModelClient::RetrieveCert(
     scoped_refptr<net::X509Certificate>* cert) {
   web::NavigationItem* item =
       web_state_->GetNavigationManager()->GetVisibleItem();
-  if (!item)
+  if (!item || !item->GetSSL().certificate)
     return false;
 
-  int cert_id = item->GetSSL().cert_id;
-  return web::CertStore::GetInstance()->RetrieveCert(cert_id, cert);
+  *cert = item->GetSSL().certificate;
+  return true;
 }
 
 bool IOSChromeSecurityStateModelClient::UsedPolicyInstalledCertificate() {
   return false;
 }
 
 bool IOSChromeSecurityStateModelClient::IsOriginSecure(const GURL& url) {
   return web::IsOriginSecure(url);
 }
 
 void IOSChromeSecurityStateModelClient::GetVisibleSecurityState(
     security_state::SecurityStateModel::VisibleSecurityState* state) {
   web::NavigationItem* item =
       web_state_->GetNavigationManager()->GetVisibleItem();
   if (!item || item->GetSSL().security_style == web::SECURITY_STYLE_UNKNOWN) {
     *state = security_state::SecurityStateModel::VisibleSecurityState();
     return;
   }
 
   state->connection_info_initialized = true;
   state->url = item->GetURL();
   const web::SSLStatus& ssl = item->GetSSL();
   state->initial_security_level =
       GetSecurityLevelForSecurityStyle(ssl.security_style);
-  state->cert_id = ssl.cert_id;
+  state->certificate = ssl.certificate;
   state->cert_status = ssl.cert_status;
   state->connection_status = ssl.connection_status;
   state->security_bits = ssl.security_bits;
   state->displayed_mixed_content =
       (ssl.content_status & web::SSLStatus::DISPLAYED_INSECURE_CONTENT) ? true
                                                                         : false;
 }