Make CertVerifier a pure virtual interface.

net/base/single_request_cert_verifier.h

Index: net/base/single_request_cert_verifier.h
diff --git a/net/base/single_request_cert_verifier.h b/net/base/single_request_cert_verifier.h
new file mode 100644
index 0000000000000000000000000000000000000000..267a15b58a4ce8f77730b3614c79f6cf1df031e7
--- /dev/null
+++ b/net/base/single_request_cert_verifier.h
@@ -0,0 +1,53 @@
+// Copyright (c) 2012 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.
+
+#ifndef NET_BASE_SINGLE_REQUEST_CERT_VERIFIER_H_
+#define NET_BASE_SINGLE_REQUEST_CERT_VERIFIER_H_
+#pragma once
+
+#include "net/base/cert_verifier.h"
+
+namespace net {
+
+// This class represents the task of verifying a certificate.  It wraps
+// CertVerifier to verify only a single certificate at a time and cancels this
+// request when going out of scope.
+class SingleRequestCertVerifier {
+ public:
+  // |cert_verifier| must remain valid for the lifetime of |this|.
+  explicit SingleRequestCertVerifier(CertVerifier* cert_verifier);
+
+  // If a completion callback is pending when the verifier is destroyed, the
+  // certificate verification is canceled, and the completion callback will
+  // not be called.
+  ~SingleRequestCertVerifier();
+
+  // Verifies the given certificate, filling out the |verify_result| object
+  // upon success. See CertVerifier::Verify() for details.
+  int Verify(X509Certificate* cert,
+             const std::string& hostname,
+             int flags,
+             CRLSet* crl_set,
+             CertVerifyResult* verify_result,
+             const CompletionCallback& callback,
+             const BoundNetLog& net_log);
+
+ private:
+  // Callback for when the request to |cert_verifier_| completes, so we
+  // dispatch to the user's callback.
+  void OnVerifyCompletion(int result);
+
+  // The actual certificate verifier that will handle the request.
+  CertVerifier* const cert_verifier_;
+
+  // The current request (if any).
+  CertVerifier::RequestHandle cur_request_;
+  CompletionCallback cur_request_callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(SingleRequestCertVerifier);
+};
+
+}  // namespace net
+
+#endif  // NET_BASE_SINGLE_REQUEST_CERT_VERIFIER_H_