Move the NSS functions out of CertDatabase into a new NSSCertDatabase class.

net/base/multi_threaded_cert_verifier.cc

Index: net/base/multi_threaded_cert_verifier.cc
diff --git a/net/base/multi_threaded_cert_verifier.cc b/net/base/multi_threaded_cert_verifier.cc
index 54e032426ba88b9686d3c54de1539938592ee8a4..3e8cf136682fddb145f0c9550ac9287686cc4425 100644
--- a/net/base/multi_threaded_cert_verifier.cc
+++ b/net/base/multi_threaded_cert_verifier.cc
@@ -382,13 +382,12 @@ MultiThreadedCertVerifier::MultiThreadedCertVerifier()
       cache_hits_(0),
       inflight_joins_(0),
       verify_proc_(CertVerifyProc::CreateDefault()) {
-  CertDatabase::AddObserver(this);
+  CertDatabase::GetInstance()->AddObserver(this);
 }
 
 MultiThreadedCertVerifier::~MultiThreadedCertVerifier() {
   STLDeleteValues(&inflight_);
-
-  CertDatabase::RemoveObserver(this);
+  CertDatabase::GetInstance()->RemoveObserver(this);
 }
 
 int MultiThreadedCertVerifier::Verify(X509Certificate* cert,