Use new BoringSSL scopers in //crypto

crypto/ec_private_key.h

Index: crypto/ec_private_key.h
diff --git a/crypto/ec_private_key.h b/crypto/ec_private_key.h
index 9cdb453e1d3de1913a58492468155eabf08fb225..917f8e1e50350c81c4b9dc1b10a90a7ee4fd6a30 100644
--- a/crypto/ec_private_key.h
+++ b/crypto/ec_private_key.h
@@ -5,6 +5,7 @@
 #ifndef CRYPTO_EC_PRIVATE_KEY_H_
 #define CRYPTO_EC_PRIVATE_KEY_H_
 
+#include <openssl/base.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ -16,9 +17,6 @@
 #include "build/build_config.h"
 #include "crypto/crypto_export.h"
 
-// Forward declaration for openssl/*.h
-typedef struct evp_pkey_st EVP_PKEY;
-
 namespace crypto {
 
 // Encapsulates an elliptic curve (EC) private key. Can be used to generate new
@@ -56,7 +54,7 @@ class CRYPTO_EXPORT ECPrivateKey {
   // Returns a copy of the object.
   std::unique_ptr<ECPrivateKey> Copy() const;
 
-  EVP_PKEY* key() { return key_; }
+  EVP_PKEY* key() { return key_.get(); }
 
   // Exports the private key to a PKCS #8 PrivateKeyInfo block.
   bool ExportPrivateKey(std::vector<uint8_t>* output) const;
@@ -83,7 +81,7 @@ class CRYPTO_EXPORT ECPrivateKey {
   // Constructor is private. Use one of the Create*() methods above instead.
   ECPrivateKey();
 
-  EVP_PKEY* key_;
+  bssl::UniquePtr<EVP_PKEY> key_;
 
   DISALLOW_COPY_AND_ASSIGN(ECPrivateKey);
 };