Allow CertNetFetcher to be shutdown from the network thread

net/cert/internal/cert_issuer_source_aia.cc

 // Copyright 2016 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/cert/internal/cert_issuer_source_aia.h"
 
 #include "base/bind.h"
 #include "net/cert/cert_net_fetcher.h"
 #include "net/cert/internal/cert_errors.h"
 #include "url/gurl.h"
@@ skipping 40 matching lines @@
     auto req = std::move(cert_fetcher_requests_[current_request_++]);
     req->WaitForResult(&error, &bytes);
 
     if (AddCompletedFetchToResults(error, std::move(bytes), out_certs))
       return;
   }
 }
 
 void AiaRequest::AddCertFetcherRequest(
     std::unique_ptr<CertNetFetcher::Request> cert_fetcher_request) {
-  DCHECK(cert_fetcher_request);
+  if (!cert_fetcher_request)
+    return;

[eroman, 2017/01/03 20:42:37]

See comment regarding interface

[estark, 2017/01/05 19:08:39]

Done.

   cert_fetcher_requests_.push_back(std::move(cert_fetcher_request));
 }
 
 bool AiaRequest::AddCompletedFetchToResults(Error error,
                                             std::vector<uint8_t> fetched_bytes,
                                             ParsedCertificateList* results) {
   if (error != OK) {
     // TODO(mattm): propagate error info.
     LOG(ERROR) << "AiaRequest::OnFetchCompleted got error " << error;
     return false;
@@ skipping 72 matching lines @@
     // that this doesn't need to wait for async callback just to tell that an
     // URL has an unsupported scheme?
     aia_request->AddCertFetcherRequest(cert_fetcher_->FetchCaIssuers(
         url, kTimeoutMilliseconds, kMaxResponseBytes));
   }
 
   *out_req = std::move(aia_request);
 }
 
 }  // namespace net