Unify the error checking of crypto::Encryptor and add WARN_UNUSED_RESULT to prevent misuse.

net/socket/dns_cert_provenance_checker.cc

 // Copyright (c) 2011 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.
 
 #include "net/socket/dns_cert_provenance_checker.h"
 
 #if !defined(USE_OPENSSL)
 
 #include <nspr.h>
 
@@ skipping 294 matching lines @@
   scoped_ptr<crypto::SymmetricKey> symkey(
       crypto::SymmetricKey::Import(crypto::SymmetricKey::AES, raw_key));
   std::string iv(key_data + kKeySizeInBytes, kIVSizeInBytes);
 
   crypto::Encryptor encryptor;
   bool r = encryptor.Init(symkey.get(), crypto::Encryptor::CBC, iv);
   CHECK(r);
 
   std::string plaintext(reinterpret_cast<const char*>(p.data()), p.size());
   std::string ciphertext;
-  encryptor.Encrypt(plaintext, &ciphertext);
+  r = encryptor.Encrypt(plaintext, &ciphertext);
+  CHECK(r);
 
   // We use another Pickle object to serialise the 'outer' wrapping of the
   // plaintext.
   Pickle outer;
   outer.WriteInt(kVersion);
 
   SECItem* pub_key_serialized = SECKEY_EncodeDERSubjectPublicKeyInfo(pub_key);
   outer.WriteString(
       std::string(reinterpret_cast<char*>(pub_key_serialized->data),
                   pub_key_serialized->len));
@@ skipping 29 matching lines @@
 
 std::string DnsCertProvenanceChecker::BuildEncryptedReport(
     const std::string& hostname,
     const std::vector<std::string>& der_certs) {
   return "";
 }
 
 }  // namespace net
 
 #endif  // USE_OPENSSL