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

crypto/signature_creator.h

 // 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.
 
 #ifndef CRYPTO_SIGNATURE_CREATOR_H_
 #define CRYPTO_SIGNATURE_CREATOR_H_
 #pragma once
 
 #include "build/build_config.h"
 
 #if defined(USE_OPENSSL)
 // Forward declaration for openssl/*.h
 typedef struct env_md_ctx_st EVP_MD_CTX;
 #elif defined(USE_NSS)
 // Forward declaration.
 struct SGNContextStr;
 #elif defined(OS_MACOSX)
 #include <Security/cssm.h>
 #endif
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "crypto/crypto_export.h"
-#include "crypto/rsa_private_key.h"
 
 #if defined(OS_WIN)
 #include "crypto/scoped_capi_types.h"
 #endif
 
 namespace crypto {
 
+class RSAPrivateKey;
+
 // Signs data using a bare private key (as opposed to a full certificate).
 // Currently can only sign data using SHA-1 with RSA encryption.
 class CRYPTO_EXPORT SignatureCreator {
  public:
   ~SignatureCreator();
 
   // Create an instance. The caller must ensure that the provided PrivateKey
   // instance outlives the created SignatureCreator.
   static SignatureCreator* Create(RSAPrivateKey* key);
 
@@ skipping 18 matching lines @@
 #elif defined(OS_WIN)
   ScopedHCRYPTHASH hash_object_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(SignatureCreator);
 };
 
 }  // namespace crypto
 
 #endif  // CRYPTO_SIGNATURE_CREATOR_H_