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

crypto/hmac.cc

Index: crypto/hmac.cc
diff --git a/crypto/hmac.cc b/crypto/hmac.cc
index c3c43da84e5c7f1265fff7bb81f431b570c18761..fa91628e33bac62c94a2247b6ddad327a785ed8d 100644
--- a/crypto/hmac.cc
+++ b/crypto/hmac.cc
@@ -63,10 +63,10 @@ bool HMAC::Sign(const base::StringPiece& data,
   DCHECK(initialized_);
 
   ScopedOpenSSLSafeSizeBuffer<EVP_MAX_MD_SIZE> result(digest, digest_length);
-  return !!::HMAC(hash_alg_ == SHA1 ? EVP_sha1() : EVP_sha256(),
-                  key_.data(), key_.size(),
+  return !!::HMAC(hash_alg_ == SHA1 ? EVP_sha1() : EVP_sha256(), key_.data(),
+                  key_.size(),
                   reinterpret_cast<const unsigned char*>(data.data()),
-                  data.size(), result.safe_buffer(), NULL);
+                  data.size(), result.safe_buffer(), nullptr);
 }
 
 bool HMAC::Verify(const base::StringPiece& data,