Clear the error bit after reading the default trusted certs

runtime/bin/secure_socket_boringssl.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #if !defined(DART_IO_DISABLED) && !defined(DART_IO_SECURE_SOCKET_DISABLED)
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_ANDROID) || \
     defined(TARGET_OS_LINUX)   || \
     defined(TARGET_OS_WINDOWS)
@@ skipping 782 matching lines @@
   CheckStatus(status, "TlsException", "Failure trusting builtint roots");
 #else
   X509_STORE* store = SSL_CTX_get_cert_store(context);
   BIO* roots_bio =
       BIO_new_mem_buf(const_cast<unsigned char*>(root_certificates_pem),
                       root_certificates_pem_length);
   X509* root_cert;
   // PEM_read_bio_X509 reads PEM-encoded certificates from a bio (in our case,
   // backed by a memory buffer), and returns X509 objects, one by one.
   // When the end of the bio is reached, it returns null.
-  while ((root_cert = PEM_read_bio_X509(roots_bio, NULL, NULL, NULL))) {
+  while ((root_cert = PEM_read_bio_X509(roots_bio, NULL, NULL, NULL)) != NULL) {
     X509_STORE_add_cert(store, root_cert);
   }
   BIO_free(roots_bio);
+  // If there is an error here, it must be the error indicating that we are done
+  // reading PEM certificates.
+  ASSERT((ERR_peek_error() == 0) || NoPEMStartLine());
+  ERR_clear_error();
 #endif  // defined(TARGET_OS_ANDROID)
 }
 
 
 static int UseChainBytesPKCS12(SSL_CTX* context,
                                BIO* bio,
                                const char* password) {
   ScopedPKCS12 p12(d2i_PKCS12_bio(bio, NULL));
   if (p12.get() == NULL) {
     return 0;
@@ skipping 867 matching lines @@
   return bytes_processed;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)
 
 #endif  // !defined(DART_IO_DISABLED) &&
         // !defined(DART_IO_SECURE_SOCKET_DISABLED)