Convert third_party source sets to static libraries.

chrome/third_party/mozilla_security_manager/BUILD.gn

 # Copyright 2015 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.
 
-source_set("mozilla_security_manager") {
+static_library("mozilla_security_manager") {
   sources = [
     "nsNSSCertHelper.cpp",
     "nsNSSCertHelper.h",
     "nsNSSCertificate.cpp",
     "nsNSSCertificate.h",
     "nsUsageArrayHelper.cpp",
     "nsUsageArrayHelper.h",
   ]
 
   deps = [
     "//base",
     "//base:i18n",
     "//chrome/app:generated_resources",
     "//crypto:platform",
     "//net",
     "//third_party/icu",
     "//ui/base",
   ]
 }