Use new BoringSSL scopers in //crypto

crypto/signature_verifier.h

 // 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.
 
 #ifndef CRYPTO_SIGNATURE_VERIFIER_H_
 #define CRYPTO_SIGNATURE_VERIFIER_H_
 
 #include <stdint.h>
 
+#include <memory>
 #include <vector>
 
 #include "build/build_config.h"
 #include "crypto/crypto_export.h"
 
 typedef struct env_md_st EVP_MD;
 typedef struct evp_pkey_ctx_st EVP_PKEY_CTX;
 
 namespace crypto {
 
@@ skipping 76 matching lines @@
                   int signature_len,
                   const uint8_t* public_key_info,
                   int public_key_info_len,
                   EVP_PKEY_CTX** pkey_ctx);
 
   void Reset();
 
   std::vector<uint8_t> signature_;
 
   struct VerifyContext;
-  VerifyContext* verify_context_;
+  std::unique_ptr<VerifyContext> verify_context_;
 };
 
 }  // namespace crypto
 
 #endif  // CRYPTO_SIGNATURE_VERIFIER_H_