Make CertVerifier a pure virtual interface.

content/browser/renderer_host/pepper_message_filter.cc

Index: content/browser/renderer_host/pepper_message_filter.cc
diff --git a/content/browser/renderer_host/pepper_message_filter.cc b/content/browser/renderer_host/pepper_message_filter.cc
index 21327c6d18bc424afa65010f2d50bbf8cf252a22..cfba6643b51610b1c8f14223701f9f97799b09cd 100644
--- a/content/browser/renderer_host/pepper_message_filter.cc
+++ b/content/browser/renderer_host/pepper_message_filter.cc
@@ -26,9 +26,9 @@
 #include "content/public/browser/site_instance.h"
 #include "content/public/common/content_client.h"
 #include "net/base/address_list.h"
-#include "net/base/cert_verifier.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/host_resolver.h"
+#include "net/base/multi_threaded_cert_verifier.h"
 #include "net/base/net_errors.h"
 #include "net/base/single_request_host_resolver.h"
 #include "ppapi/c/pp_errors.h"
@@ -142,7 +142,7 @@ net::HostResolver* PepperMessageFilter::GetHostResolver() {
 
 net::CertVerifier* PepperMessageFilter::GetCertVerifier() {
   if (!cert_verifier_.get())
-    cert_verifier_.reset(new net::CertVerifier());
+    cert_verifier_.reset(new net::MultiThreadedCertVerifier());
 
   return cert_verifier_.get();
 }