Replace Scoped* heap types with bssl::UniquePtr.

Unlike the Scoped* types, bssl::UniquePtr is available to C++ users, and
offered for a large variety of types.  The 'extern "C++"' trick is used
to make the C++ bits digestible to C callers that wrap header files in
'extern "C"'.

Change-Id: Ifbca4c2997d6628e33028c7d7620c72aff0f862e
Reviewed-on: https://boringssl-review.googlesource.com/10521
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

tool/genrsa.cc

diff --git a/tool/genrsa.cc b/tool/genrsa.cc
index 4b39401..b49ebbc 100644
--- a/tool/genrsa.cc
+++ b/tool/genrsa.cc
@@ -18,7 +18,6 @@
 #include <openssl/pem.h>
 #include <openssl/rsa.h>
 
-#include "../crypto/test/scoped_types.h"
 #include "internal.h"
 
 
@@ -51,9 +50,9 @@
     return false;
   }
 
-  ScopedRSA rsa(RSA_new());
-  ScopedBIGNUM e(BN_new());
-  ScopedBIO bio(BIO_new_fp(stdout, BIO_NOCLOSE));
+  bssl::UniquePtr<RSA> rsa(RSA_new());
+  bssl::UniquePtr<BIGNUM> e(BN_new());
+  bssl::UniquePtr<BIO> bio(BIO_new_fp(stdout, BIO_NOCLOSE));
 
   if (!BN_set_word(e.get(), RSA_F4) ||
       !RSA_generate_multi_prime_key(rsa.get(), bits, nprimes, e.get(), NULL) ||