Initial support for HSTS certificate locking. This isn't a finished work, but

net/base/x509_cert_types.cc

Index: net/base/x509_cert_types.cc
===================================================================
--- net/base/x509_cert_types.cc	(revision 80507)
+++ net/base/x509_cert_types.cc	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -8,6 +8,7 @@
 #include "base/logging.h"
 #include "base/string_number_conversions.h"
 #include "base/string_piece.h"
+#include "base/string_util.h"
 #include "base/time.h"
 
 namespace net {
@@ -27,6 +28,13 @@
 
 }  // namespace
 
+std::string SHA1Fingerprint::GetString() const {
+  std::string hash;
+  for (size_t i = 0; i < sizeof(data); ++i)
+    hash += StringPrintf("%02x", data[i]);
+  return hash;
+}
+
 CertPrincipal::CertPrincipal() {
 }