From: Hans Petter Jansson <hpj@copyleft.no>
      Wolfgang Rosenauer <wr@rosenauer.org>
Subject: use libnsssharedhelper if available at compile time
         (can be disabled by exporting MOZ_XRE_NO_NSSHELPER=1)
References:

diff --git a/old-configure.in b/old-configure.in
--- a/old-configure.in
+++ b/old-configure.in
@@ -6495,16 +6495,31 @@ if test "$MOZ_ENABLE_SKIA"; then
     AC_DEFINE(USE_SKIA_GPU)
     AC_SUBST(MOZ_ENABLE_SKIA_GPU)
   fi
 fi
 AC_SUBST(MOZ_ENABLE_SKIA)
 AC_SUBST_LIST(SKIA_INCLUDES)
 
 dnl ========================================================
+dnl Check for nss-shared-helper
+dnl ========================================================
+
+  PKG_CHECK_MODULES(NSSHELPER, nss-shared-helper,
+    [MOZ_ENABLE_NSSHELPER=1],
+    [MOZ_ENABLE_NSSHELPER=])
+
+if test "$MOZ_ENABLE_NSSHELPER"; then
+  AC_DEFINE(MOZ_ENABLE_NSSHELPER)
+fi
+AC_SUBST(MOZ_ENABLE_NSSHELPER)
+AC_SUBST_LIST(NSSHELPER_CFLAGS)
+AC_SUBST_LIST(NSSHELPER_LIBS)
+
+dnl ========================================================
 dnl disable xul
 dnl ========================================================
 MOZ_ARG_DISABLE_BOOL(xul,
 [  --disable-xul           Disable XUL],
     MOZ_XUL= )
 if test "$MOZ_XUL"; then
   AC_DEFINE(MOZ_XUL)
 else
diff --git a/security/manager/ssl/moz.build b/security/manager/ssl/moz.build
--- a/security/manager/ssl/moz.build
+++ b/security/manager/ssl/moz.build
@@ -159,16 +159,19 @@ if CONFIG['MOZ_XUL']:
     ]
 
 UNIFIED_SOURCES += [
     'md4.c',
 ]
 
 FINAL_LIBRARY = 'xul'
 
+CXXFLAGS += sorted(CONFIG['NSSHELPER_CFLAGS'])
+OS_LIBS += sorted(CONFIG['NSSHELPER_LIBS'])
+
 LOCAL_INCLUDES += [
     '/dom/base',
     '/dom/crypto',
     '/security/certverifier',
     '/security/pkix/include',
 ]
 
 LOCAL_INCLUDES += [
diff --git a/security/manager/ssl/nsNSSComponent.cpp b/security/manager/ssl/nsNSSComponent.cpp
--- a/security/manager/ssl/nsNSSComponent.cpp
+++ b/security/manager/ssl/nsNSSComponent.cpp
@@ -1,14 +1,21 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#ifdef MOZ_ENABLE_NSSHELPER
+#pragma GCC visibility push(default)
+#include <nss-shared-helper.h>
+#pragma GCC visibility pop
+#include "prenv.h"
+#endif
+
 #include "nsNSSComponent.h"
 
 #include "ExtendedValidation.h"
 #include "NSSCertDBTrustDomain.h"
 #include "ScopedNSSTypes.h"
 #include "SharedSSLState.h"
 #include "cert.h"
 #include "certdb.h"
@@ -1491,17 +1498,31 @@ nsNSSComponent::InitializeNSS()
       return rv;
     }
   }
   MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("inSafeMode: %u\n", inSafeMode));
 
   if (!nocertdb && !profileStr.IsEmpty()) {
     // First try to initialize the NSS DB in read/write mode.
     // Only load PKCS11 modules if we're not in safe mode.
+#ifdef MOZ_ENABLE_NSSHELPER
+    if (PR_GetEnv("MOZ_XRE_NO_NSSHELPER")) {
+      init_rv = ::mozilla::psm::InitializeNSS(profileStr.get(), false, !inSafeMode);
+    } else {
+      uint32_t flags = NSS_INIT_NOROOTINIT | NSS_INIT_OPTIMIZESPACE;
+      init_rv = ::nsshelp_open_db ("Firefox", profileStr.get(), flags);
+
+      if (init_rv != SECSuccess) {
+        MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("can not init NSS using nsshelp_open_db in %s\n", profileStr.get()));
+        init_rv = ::mozilla::psm::InitializeNSS(profileStr.get(), false, !inSafeMode);
+      }
+    }
+#else
     init_rv = ::mozilla::psm::InitializeNSS(profileStr.get(), false, !inSafeMode);
+#endif
     // If that fails, attempt read-only mode.
     if (init_rv != SECSuccess) {
       MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("could not init NSS r/w in %s\n", profileStr.get()));
       init_rv = ::mozilla::psm::InitializeNSS(profileStr.get(), true, !inSafeMode);
     }
     if (init_rv != SECSuccess) {
       MOZ_LOG(gPIPNSSLog, LogLevel::Debug, ("could not init in r/o either\n"));
     }
diff --git a/toolkit/library/moz.build b/toolkit/library/moz.build
--- a/toolkit/library/moz.build
+++ b/toolkit/library/moz.build
@@ -209,16 +209,18 @@ if CONFIG['OS_ARCH'] == 'Linux' and CONF
     OS_LIBS += [
         'rt',
     ]
 
 OS_LIBS += CONFIG['MOZ_CAIRO_OSLIBS']
 OS_LIBS += CONFIG['MOZ_WEBRTC_X11_LIBS']
 OS_LIBS += CONFIG['MOZ_SERVO_LIBS']
 
+OS_LIBS += sorted(CONFIG['NSSHELPER_LIBS'])
+
 if CONFIG['MOZ_SYSTEM_JPEG']:
     OS_LIBS += CONFIG['MOZ_JPEG_LIBS']
 
 if CONFIG['MOZ_SYSTEM_PNG']:
     OS_LIBS += CONFIG['MOZ_PNG_LIBS']
 
 if CONFIG['MOZ_SYSTEM_HUNSPELL']:
     OS_LIBS += CONFIG['MOZ_HUNSPELL_LIBS']