Make //crypto factories return std::unique_ptr<>s

crypto/symmetric_key.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_SYMMETRIC_KEY_H_
 #define CRYPTO_SYMMETRIC_KEY_H_
 
 #include <stddef.h>
 
+#include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "crypto/crypto_export.h"
 
 namespace crypto {
 
 // Wraps a platform-specific symmetric key and allows it to be held in a
 // scoped_ptr.
 class CRYPTO_EXPORT SymmetricKey {
  public:
   // Defines the algorithm that a key will be used with. See also
   // classs Encrptor.
   enum Algorithm {
     AES,
     HMAC_SHA1,
   };
 
   virtual ~SymmetricKey();
 
   // Generates a random key suitable to be used with |algorithm| and of
   // |key_size_in_bits| bits. |key_size_in_bits| must be a multiple of 8.
   // The caller is responsible for deleting the returned SymmetricKey.
-  static SymmetricKey* GenerateRandomKey(Algorithm algorithm,
-                                         size_t key_size_in_bits);
+  static std::unique_ptr<SymmetricKey> GenerateRandomKey(
+      Algorithm algorithm,
+      size_t key_size_in_bits);
 
   // Derives a key from the supplied password and salt using PBKDF2, suitable
   // for use with specified |algorithm|. Note |algorithm| is not the algorithm
   // used to derive the key from the password. |key_size_in_bits| must be a
   // multiple of 8. The caller is responsible for deleting the returned
   // SymmetricKey.
-  static SymmetricKey* DeriveKeyFromPassword(Algorithm algorithm,
-                                             const std::string& password,
-                                             const std::string& salt,
-                                             size_t iterations,
-                                             size_t key_size_in_bits);
+  static std::unique_ptr<SymmetricKey> DeriveKeyFromPassword(
+      Algorithm algorithm,
+      const std::string& password,
+      const std::string& salt,
+      size_t iterations,
+      size_t key_size_in_bits);
 
   // Imports an array of key bytes in |raw_key|. This key may have been
   // generated by GenerateRandomKey or DeriveKeyFromPassword and exported with
   // GetRawKey, or via another compatible method. The key must be of suitable
   // size for use with |algorithm|. The caller owns the returned SymmetricKey.
-  static SymmetricKey* Import(Algorithm algorithm, const std::string& raw_key);
+  static std::unique_ptr<SymmetricKey> Import(Algorithm algorithm,
+                                              const std::string& raw_key);
 
   const std::string& key() { return key_; }
 
   // Extracts the raw key from the platform specific data.
   // Warning: |raw_key| holds the raw key as bytes and thus must be handled
   // carefully.
   bool GetRawKey(std::string* raw_key);
 
  private:
-  SymmetricKey() {}
+  SymmetricKey();
+
   std::string key_;
 
   DISALLOW_COPY_AND_ASSIGN(SymmetricKey);
 };
 
 }  // namespace crypto
 
 #endif  // CRYPTO_SYMMETRIC_KEY_H_