Revert of Move JoinString to the base namespace

chrome/browser/ssl/ssl_blocking_page.cc

 // Copyright (c) 2012 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 "chrome/browser/ssl/ssl_blocking_page.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/build_time.h"
 #include "base/callback_helpers.h"
@@ skipping 437 matching lines @@
       "issuer", ssl_info_.cert->issuer().GetDisplayName());
   load_time_data->SetString(
       "expirationDate",
       base::TimeFormatShortDate(ssl_info_.cert->valid_expiry()));
   load_time_data->SetString(
       "currentDate", base::TimeFormatShortDate(time_triggered_));
   std::vector<std::string> encoded_chain;
   ssl_info_.cert->GetPEMEncodedChain(
       &encoded_chain);
   load_time_data->SetString(
-      "pem", base::JoinString(encoded_chain, base::StringPiece()));
+      "pem", JoinString(encoded_chain, std::string()));
 
   cert_report_helper_->PopulateExtendedReportingOption(load_time_data);
 }
 
 void SSLBlockingPage::OverrideEntry(NavigationEntry* entry) {
   int cert_id = content::CertStore::GetInstance()->StoreCert(
       ssl_info_.cert.get(), web_contents()->GetRenderProcessHost()->GetID());
   DCHECK(cert_id);
 
   entry->GetSSL().security_style =
@@ skipping 176 matching lines @@
       !(options_mask & SSLBlockingPage::STRICT_ENFORCEMENT) &&
       profile->GetPrefs()->GetBoolean(prefs::kSSLErrorOverrideAllowed);
   return is_overridable;
 }
 
 // static
 bool SSLBlockingPage::DoesPolicyAllowDangerOverride(
     const Profile* const profile) {
   return profile->GetPrefs()->GetBoolean(prefs::kSSLErrorOverrideAllowed);
 }