CertificateProviderService: Expose certificate lookup.

chrome/browser/chromeos/certificate_provider/sign_requests.cc

 // Copyright 2015 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 "chrome/browser/chromeos/certificate_provider/sign_requests.h"
 
 #include "base/callback.h"
 
 namespace chromeos {
 namespace certificate_provider {
@@ skipping 17 matching lines @@
 bool SignRequests::RemoveRequest(const std::string& extension_id,
                                  int request_id,
                                  net::SSLPrivateKey::SignCallback* callback) {
   RequestsState& state = extension_to_requests_[extension_id];
   std::map<int, net::SSLPrivateKey::SignCallback>& pending =
       state.pending_requests;
   const auto it = pending.find(request_id);
   if (it == pending.end())
     return false;
 
-  *callback = it->second;
+  if (callback)
+    *callback = it->second;
   pending.erase(it);
   return true;
 }
 
 std::vector<net::SSLPrivateKey::SignCallback> SignRequests::RemoveAllRequests(
     const std::string& extension_id) {
   std::vector<net::SSLPrivateKey::SignCallback> callbacks;
   for (const auto& entry :
        extension_to_requests_[extension_id].pending_requests) {
     callbacks.push_back(entry.second);
   }
   extension_to_requests_.erase(extension_id);
   return callbacks;
 }
 
 }  // namespace certificate_provider
 }  // namespace chromeos