Make CertVerifier a pure virtual interface.

net/socket/ssl_client_socket_unittest.cc

Index: net/socket/ssl_client_socket_unittest.cc
diff --git a/net/socket/ssl_client_socket_unittest.cc b/net/socket/ssl_client_socket_unittest.cc
index bf156d1a550c5811a6ddeb2b5d40222959f7c772..ab31859063c61e6ecd28f1812665dd920fdd7377 100644
--- a/net/socket/ssl_client_socket_unittest.cc
+++ b/net/socket/ssl_client_socket_unittest.cc
@@ -5,9 +5,9 @@
 #include "net/socket/ssl_client_socket.h"
 
 #include "net/base/address_list.h"
-#include "net/base/cert_verifier.h"
 #include "net/base/host_resolver.h"
 #include "net/base/io_buffer.h"
+#include "net/base/multi_threaded_cert_verifier.h"
 #include "net/base/net_log.h"
 #include "net/base/net_log_unittest.h"
 #include "net/base/net_errors.h"
@@ -29,7 +29,7 @@ class SSLClientSocketTest : public PlatformTest {
  public:
   SSLClientSocketTest()
       : socket_factory_(net::ClientSocketFactory::GetDefaultFactory()),
-        cert_verifier_(new net::CertVerifier) {
+        cert_verifier_(new net::MultiThreadedCertVerifier) {
   }
 
  protected: