Add crypto/wincrypt_shim.h wrapper header to resolve BoringSSL conflicts.

crypto/capi_util.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_CAPI_UTIL_H_
 #define CRYPTO_CAPI_UTIL_H_
 
 #include <windows.h>
-#include <wincrypt.h>
 
 #include "crypto/crypto_export.h"
+#include "crypto/wincrypt_shim.h"
 
 namespace crypto {
 
 // CryptAcquireContext when passed CRYPT_NEWKEYSET or CRYPT_DELETEKEYSET in
 // flags is not thread-safe. For such calls, we create a global lock to
 // synchronize it.
 //
 // From "Threading Issues with Cryptographic Service Providers",
 // <http://msdn.microsoft.com/en-us/library/aa388149(v=VS.85).aspx>:
 //
 // "The CryptAcquireContext function is generally thread safe unless
 // CRYPT_NEWKEYSET or CRYPT_DELETEKEYSET is specified in the dwFlags
 // parameter."
 CRYPTO_EXPORT BOOL CryptAcquireContextLocked(HCRYPTPROV* prov,
                                              LPCWSTR container,
                                              LPCWSTR provider,
                                              DWORD prov_type,
                                              DWORD flags);
 
 // Wrappers of malloc and free for CryptoAPI routines that need memory
 // allocators, such as in CRYPT_DECODE_PARA. Such routines require WINAPI
 // calling conventions.
 CRYPTO_EXPORT void* WINAPI CryptAlloc(size_t size);
 CRYPTO_EXPORT void WINAPI CryptFree(void* p);
 
 }  // namespace crypto
 
 #endif  // CRYPTO_CAPI_UTIL_H_