Fix non-noise cpplint errors in //crypto.

crypto/signature_creator_unittest.cc

 // 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.
 
 #include "crypto/signature_creator.h"
 
 #include <stdint.h>
 
 #include <memory>
+#include <string>
 #include <vector>
 
 #include "base/sha1.h"
 #include "crypto/rsa_private_key.h"
 #include "crypto/sha2.h"
 #include "crypto/signature_verifier.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 TEST(SignatureCreatorTest, BasicTest) {
   // Do a verify round trip.
@@ skipping 93 matching lines @@
   // Verify the input data.
   crypto::SignatureVerifier verifier;
   ASSERT_TRUE(verifier.VerifyInit(
       crypto::SignatureVerifier::RSA_PKCS1_SHA256, &signature.front(),
       signature.size(), &public_key_info.front(), public_key_info.size()));
 
   verifier.VerifyUpdate(reinterpret_cast<const uint8_t*>(data.c_str()),
                         data.size());
   ASSERT_TRUE(verifier.VerifyFinal());
 }