NACL_WIN64 takes precedence over USE_OPENSSL.

crypto/symmetric_key.h

 // 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.
 
 #ifndef CRYPTO_SYMMETRIC_KEY_H_
 #define CRYPTO_SYMMETRIC_KEY_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 39 matching lines @@
                                              const std::string& salt,
                                              size_t iterations,
                                              size_t key_size_in_bits);
 
   // Imports an array of key bytes in |raw_key|. This key may have been
   // generated by GenerateRandomKey or DeriveKeyFromPassword and exported with
   // GetRawKey, or via another compatible method. The key must be of suitable
   // size for use with |algorithm|. The caller owns the returned SymmetricKey.
   static SymmetricKey* Import(Algorithm algorithm, const std::string& raw_key);
 
-#if defined(USE_OPENSSL)
+#if defined(NACL_WIN64)
+  HCRYPTKEY key() const { return key_.get(); }
+#elif defined(USE_OPENSSL)
   const std::string& key() { return key_; }
-#elif defined(NACL_WIN64)
-  HCRYPTKEY key() const { return key_.get(); }
 #elif defined(USE_NSS) || defined(OS_WIN) || defined(OS_MACOSX)
   PK11SymKey* key() const { return key_.get(); }
 #endif
 
   // Extracts the raw key from the platform specific data.
   // Warning: |raw_key| holds the raw key as bytes and thus must be handled
   // carefully.
   bool GetRawKey(std::string* raw_key);
 
  private:
-#if defined(USE_OPENSSL)
-  SymmetricKey() {}
-  std::string key_;
-#elif defined(NACL_WIN64)
+#if defined(NACL_WIN64)
   SymmetricKey(HCRYPTPROV provider, HCRYPTKEY key,
                const void* key_data, size_t key_size_in_bytes);
 
   ScopedHCRYPTPROV provider_;
   ScopedHCRYPTKEY key_;
 
   // Contains the raw key, if it is known during initialization and when it
   // is likely that the associated |provider_| will be unable to export the
   // |key_|. This is the case of HMAC keys when the key size exceeds 16 bytes
   // when using the default RSA provider.
   // TODO(rsleevi): See if KP_EFFECTIVE_KEYLEN is the reason why CryptExportKey
   // fails with NTE_BAD_KEY/NTE_BAD_LEN
   std::string raw_key_;
+#elif defined(USE_OPENSSL)
+  SymmetricKey() {}
+  std::string key_;
 #elif defined(USE_NSS) || defined(OS_WIN) || defined(OS_MACOSX)
   explicit SymmetricKey(PK11SymKey* key);
   ScopedPK11SymKey key_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(SymmetricKey);
 };
 
 }  // namespace crypto
 
 #endif  // CRYPTO_SYMMETRIC_KEY_H_