Use a forward declaration of RSAPrivateKey in crypto/signature_creator.h.

crypto/signature_creator_unittest.cc

 // Copyright (c) 2011 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 <vector>
 
 #include "base/memory/scoped_ptr.h"
+#include "crypto/rsa_private_key.h"
 #include "crypto/signature_creator.h"
 #include "crypto/signature_verifier.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 TEST(SignatureCreatorTest, BasicTest) {
   // Do a verify round trip.
   scoped_ptr<crypto::RSAPrivateKey> key_original(
       crypto::RSAPrivateKey::Create(1024));
   ASSERT_TRUE(key_original.get());
 
@@ skipping 26 matching lines @@
   crypto::SignatureVerifier verifier;
   ASSERT_TRUE(verifier.VerifyInit(
       kSHA1WithRSAAlgorithmID, sizeof(kSHA1WithRSAAlgorithmID),
       &signature.front(), signature.size(),
       &public_key_info.front(), public_key_info.size()));
 
   verifier.VerifyUpdate(reinterpret_cast<const uint8*>(data.c_str()),
                         data.size());
   ASSERT_TRUE(verifier.VerifyFinal());
 }