Switch Windows over to BoringSSL from NSS.

net/ssl/openssl_platform_key_win.cc

Index: net/ssl/openssl_platform_key_win.cc
diff --git a/net/ssl/openssl_platform_key_win.cc b/net/ssl/openssl_platform_key_win.cc
index 8c9589afe0d0247edd887dfa7a897d6f4f6a38c6..81e2ed91a1dd44183361e54835eed0ff5ef0a636 100644
--- a/net/ssl/openssl_platform_key_win.cc
+++ b/net/ssl/openssl_platform_key_win.cc
@@ -506,7 +506,7 @@ int EcdsaMethodSign(const uint8_t* digest,
 
   // Ensure the DER-encoded signature fits in the bounds.
   int len = i2d_ECDSA_SIG(sig.get(), nullptr);
-  if (len < 0 || len > ECDSA_size(ec_key)) {
+  if (len < 0 || static_cast<size_t>(len) > ECDSA_size(ec_key)) {
     OpenSSLPutNetError(FROM_HERE, ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED);
     return 0;
   }