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>
diff --git a/crypto/ecdsa/ecdsa_verify_test.cc b/crypto/ecdsa/ecdsa_verify_test.cc
index 7ef2d29..18340e2 100644
--- a/crypto/ecdsa/ecdsa_verify_test.cc
+++ b/crypto/ecdsa/ecdsa_verify_test.cc
@@ -21,58 +21,59 @@
 #include <openssl/ec.h>
 #include <openssl/ec_key.h>
 #include <openssl/ecdsa.h>
+#include <openssl/nid.h>
 
 #include "../test/file_test.h"
-#include "../test/scoped_types.h"
 
 
-static ScopedEC_GROUP GetCurve(FileTest *t, const char *key) {
+static bssl::UniquePtr<EC_GROUP> GetCurve(FileTest *t, const char *key) {
   std::string curve_name;
   if (!t->GetAttribute(&curve_name, key)) {
     return nullptr;
   }
 
   if (curve_name == "P-224") {
-    return ScopedEC_GROUP(EC_GROUP_new_by_curve_name(NID_secp224r1));
+    return bssl::UniquePtr<EC_GROUP>(EC_GROUP_new_by_curve_name(NID_secp224r1));
   }
   if (curve_name == "P-256") {
-    return ScopedEC_GROUP(EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1));
+    return bssl::UniquePtr<EC_GROUP>(
+        EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1));
   }
   if (curve_name == "P-384") {
-    return ScopedEC_GROUP(EC_GROUP_new_by_curve_name(NID_secp384r1));
+    return bssl::UniquePtr<EC_GROUP>(EC_GROUP_new_by_curve_name(NID_secp384r1));
   }
   if (curve_name == "P-521") {
-    return ScopedEC_GROUP(EC_GROUP_new_by_curve_name(NID_secp521r1));
+    return bssl::UniquePtr<EC_GROUP>(EC_GROUP_new_by_curve_name(NID_secp521r1));
   }
 
   t->PrintLine("Unknown curve '%s'", curve_name.c_str());
   return nullptr;
 }
 
-static ScopedBIGNUM GetBIGNUM(FileTest *t, const char *key) {
+static bssl::UniquePtr<BIGNUM> GetBIGNUM(FileTest *t, const char *key) {
   std::vector<uint8_t> bytes;
   if (!t->GetBytes(&bytes, key)) {
     return nullptr;
   }
 
-  return ScopedBIGNUM(BN_bin2bn(bytes.data(), bytes.size(), nullptr));
+  return bssl::UniquePtr<BIGNUM>(BN_bin2bn(bytes.data(), bytes.size(), nullptr));
 }
 
 static bool TestECDSASign(FileTest *t, void *arg) {
-  ScopedEC_GROUP group = GetCurve(t, "Curve");
-  ScopedBIGNUM x = GetBIGNUM(t, "X");
-  ScopedBIGNUM y = GetBIGNUM(t, "Y");
-  ScopedBIGNUM r = GetBIGNUM(t, "R");
-  ScopedBIGNUM s = GetBIGNUM(t, "S");
+  bssl::UniquePtr<EC_GROUP> group = GetCurve(t, "Curve");
+  bssl::UniquePtr<BIGNUM> x = GetBIGNUM(t, "X");
+  bssl::UniquePtr<BIGNUM> y = GetBIGNUM(t, "Y");
+  bssl::UniquePtr<BIGNUM> r = GetBIGNUM(t, "R");
+  bssl::UniquePtr<BIGNUM> s = GetBIGNUM(t, "S");
   std::vector<uint8_t> digest;
   if (!group || !x || !y || !r || !s ||
       !t->GetBytes(&digest, "Digest")) {
     return false;
   }
 
-  ScopedEC_KEY key(EC_KEY_new());
-  ScopedEC_POINT pub_key(EC_POINT_new(group.get()));
-  ScopedECDSA_SIG sig(ECDSA_SIG_new());
+  bssl::UniquePtr<EC_KEY> key(EC_KEY_new());
+  bssl::UniquePtr<EC_POINT> pub_key(EC_POINT_new(group.get()));
+  bssl::UniquePtr<ECDSA_SIG> sig(ECDSA_SIG_new());
   if (!key || !pub_key || !sig ||
       !EC_KEY_set_group(key.get(), group.get()) ||
       !EC_POINT_set_affine_coordinates_GFp(group.get(), pub_key.get(), x.get(),