Use span in RSAPrivateKey factory method

Use base::span for accepting the input in the
crypto::RSAPrivateKey::CreateFromPrivateKeyInfo() method.

This allows to make using this method slightly more convenient, without
needing to convert the data into std::vector<uint8_t>.

This is a pure refactoring CL; no functional changes expected.

Bug: 1067683
Change-Id: I180980cabf868d464eb5278332a3d06cd119246d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2270446
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: David Benjamin <davidben@chromium.org>
Cr-Commit-Position: refs/heads/master@{#783593}

crypto/rsa_private_key.cc

@@ -10,6 +10,7 @@
 #include <utility>
 
 #include "base/check.h"
+#include "base/containers/span.h"
 #include "crypto/openssl_util.h"
 #include "third_party/boringssl/src/include/openssl/bn.h"
 #include "third_party/boringssl/src/include/openssl/bytestring.h"
@@ -41,7 +42,7 @@ std::unique_ptr<RSAPrivateKey> RSAPrivateKey::Create(uint16_t num_bits) {
 
 // static
 std::unique_ptr<RSAPrivateKey> RSAPrivateKey::CreateFromPrivateKeyInfo(
-    const std::vector<uint8_t>& input) {
+    base::span<const uint8_t> input) {
   OpenSSLErrStackTracer err_tracer(FROM_HERE);
 
   CBS cbs;

crypto/rsa_private_key.h

@@ -11,6 +11,7 @@
 #include <memory>
 #include <vector>
 
+#include "base/containers/span.h"
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "crypto/crypto_export.h"
@@ -32,7 +33,7 @@ class CRYPTO_EXPORT RSAPrivateKey {
   // an ASN.1-encoded PrivateKeyInfo block from PKCS #8. This can return NULL if
   // initialization fails.
   static std::unique_ptr<RSAPrivateKey> CreateFromPrivateKeyInfo(
-      const std::vector<uint8_t>& input);
+      base::span<const uint8_t> input);
 
   // Create a new instance from an existing EVP_PKEY, taking a
   // reference to it. |key| must be an RSA key. Returns NULL on