Change uses of base::JoinString to pass StringPieces where possible.

extensions/browser/api/bluetooth/bluetooth_private_api.cc

 // Copyright 2014 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 "extensions/browser/api/bluetooth/bluetooth_private_api.h"
 
 #include <stdint.h>
 
 #include <utility>
 
 #include "base/callback.h"
 #include "base/lazy_instance.h"
+#include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 #include "device/bluetooth/bluetooth_adapter_factory.h"
 #include "device/bluetooth/bluetooth_common.h"
 #include "device/bluetooth/bluetooth_discovery_session.h"
 #include "extensions/browser/api/bluetooth/bluetooth_api.h"
 #include "extensions/browser/api/bluetooth/bluetooth_api_pairing_delegate.h"
 #include "extensions/browser/api/bluetooth/bluetooth_event_router.h"
 #include "extensions/common/api/bluetooth_private.h"
 
@@ skipping 200 matching lines @@
   pending_properties_.erase(property);
   failed_properties_.insert(property);
   if (pending_properties_.empty() && parsed_)
     SendError();
 }
 
 void BluetoothPrivateSetAdapterStateFunction::SendError() {
   DCHECK(pending_properties_.empty());
   DCHECK(!failed_properties_.empty());
 
-  std::vector<std::string> failed_vector;
-  std::copy(failed_properties_.begin(), failed_properties_.end(),
-            std::back_inserter(failed_vector));
+  std::vector<base::StringPiece> failed_vector(failed_properties_.begin(),
+                                               failed_properties_.end());
 
   std::vector<std::string> replacements(1);
   replacements[0] = base::JoinString(failed_vector, ", ");
   std::string error = base::ReplaceStringPlaceholders(kSetAdapterPropertyError,
                                                       replacements, nullptr);
   SetError(error);
   SendResponse(false);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
@@ skipping 350 matching lines @@
     device::BluetoothDevice::ConnectErrorCode error) {
   SetError(kPairingFailed);
   SendResponse(false);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 }  // namespace api
 
 }  // namespace extensions