Do not take references of temporary objects

Some compilers are less forgiving about this than clang.

Change-Id: Iad07f21fcc38b8701c7c05609048805114d2ef44
Reviewed-on: https://chromium-review.googlesource.com/c/1201854
Commit-Queue: Kim Paulhamus <kpaulhamus@chromium.org>
Reviewed-by: Kim Paulhamus <kpaulhamus@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632752}

device/fido/u2f_register_operation.cc

@@ -58,7 +58,7 @@ void U2fRegisterOperation::TryRegistration(bool is_duplicate_registration) {
 void U2fRegisterOperation::OnRegisterResponseReceived(
     bool is_duplicate_registration,
     base::Optional<std::vector<uint8_t>> device_response) {
-  const auto& apdu_response =
+  const auto apdu_response =
       device_response
           ? apdu::ApduResponse::CreateFromMessage(std::move(*device_response))
           : base::nullopt;
@@ -103,7 +103,7 @@ void U2fRegisterOperation::OnRegisterResponseReceived(
 void U2fRegisterOperation::OnCheckForExcludedKeyHandle(
     ExcludeListIterator it,
     base::Optional<std::vector<uint8_t>> device_response) {
-  const auto& apdu_response =
+  const auto apdu_response =
       device_response
           ? apdu::ApduResponse::CreateFromMessage(std::move(*device_response))
           : base::nullopt;

device/fido/u2f_sign_operation.cc

@@ -130,7 +130,7 @@ void U2fSignOperation::OnCheckForKeyHandlePresence(
     AllowedListIterator it,
     base::Optional<std::vector<uint8_t>> device_response) {
   DCHECK(request().allow_list());
-  const auto& apdu_response =
+  const auto apdu_response =
       device_response
           ? apdu::ApduResponse::CreateFromMessage(std::move(*device_response))
           : base::nullopt;