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

components/os_crypt/os_crypt_mac.mm

Index: components/os_crypt/os_crypt_mac.mm
diff --git a/components/os_crypt/os_crypt_mac.mm b/components/os_crypt/os_crypt_mac.mm
index 66f77c296754393677dac5350cf3b1b2e35d37ac..5b97726ae83f4ebe2b183446d3314fbbdd1f50b1 100644
--- a/components/os_crypt/os_crypt_mac.mm
+++ b/components/os_crypt/os_crypt_mac.mm
@@ -77,12 +77,10 @@ crypto::SymmetricKey* GetEncryptionKey() {
 
   // Create an encryption key from our password and salt. The key is
   // intentionally leaked.
-  cached_encryption_key =
-      crypto::SymmetricKey::DeriveKeyFromPassword(crypto::SymmetricKey::AES,
-                                                  password,
-                                                  salt,
-                                                  kEncryptionIterations,
-                                                  kDerivedKeySizeInBits);
+  cached_encryption_key = crypto::SymmetricKey::DeriveKeyFromPassword(
+                              crypto::SymmetricKey::AES, password, salt,
+                              kEncryptionIterations, kDerivedKeySizeInBits)
+                              .release();
   ANNOTATE_LEAKING_OBJECT_PTR(cached_encryption_key);
   DCHECK(cached_encryption_key);
   return cached_encryption_key;