Add async variant of ProofSource::GetProof

net/quic/crypto/proof_source_chromium.cc

 // Copyright 2013 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/quic/crypto/proof_source_chromium.h"
 
 #include <openssl/digest.h>
 #include <openssl/evp.h>
 #include <openssl/rsa.h>
 
@@ skipping 133 matching lines @@
   signature.resize(len);
   out_signature->assign(reinterpret_cast<const char*>(signature.data()),
                         signature.size());
   *out_chain = chain_;
   VLOG(1) << "signature: "
           << base::HexEncode(out_signature->data(), out_signature->size());
   *out_leaf_cert_sct = signed_certificate_timestamp_;
   return true;
 }
 
+void ProofSourceChromium::GetProof(const IPAddress& server_ip,
+                                   const std::string& hostname,
+                                   const std::string& server_config,
+                                   QuicVersion quic_version,
+                                   base::StringPiece chlo_hash,
+                                   bool ecdsa_ok,
+                                   std::unique_ptr<Callback> callback) {
+  // As a transitional implementation, just call the synchronous version of
+  // GetProof, then invoke the callback with the results and destroy it.
+  // TODO(gredner): rework this when GetProof involves an RPC.  At that point
+  // this class will also need to store a pointer to the callback and ensure
+  // that it gets deleted after it is invoked.

[Ryan Hamilton, 2016/07/07 16:34:00]

Since proof_source_chromium is not shared, I think we'll ever end up doing an
RPC. So how 'bout just nuking this comment?

+  scoped_refptr<ProofSource::Chain> chain;
+  string signature;
+  string leaf_cert_sct;
+  const bool ok =
+      GetProof(server_ip, hostname, server_config, quic_version, chlo_hash,
+               ecdsa_ok, &chain, &signature, &leaf_cert_sct);
+  callback->Run(ok, chain, signature, leaf_cert_sct);
+}
+
 }  // namespace net