Run clang-modernize -use-nullptr over src/extensions/.

extensions/browser/api/dns/mock_host_resolver_creator.cc

 // Copyright 2014 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.
 
 #include "extensions/browser/api/dns/mock_host_resolver_creator.h"
 
 #include "base/logging.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/dns/mock_host_resolver.h"
 
 using content::BrowserThread;
 
 namespace extensions {
 
 const std::string MockHostResolverCreator::kHostname = "www.sowbug.com";
 const std::string MockHostResolverCreator::kAddress = "9.8.7.6";
 
 MockHostResolverCreator::MockHostResolverCreator()
-    : resolver_event_(true, false), mock_host_resolver_(NULL) {
+    : resolver_event_(true, false), mock_host_resolver_(nullptr) {
 }
 
 MockHostResolverCreator::~MockHostResolverCreator() {
 }
 
 net::HostResolver* MockHostResolverCreator::CreateMockHostResolver() {
   DCHECK(!mock_host_resolver_);
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   bool result = BrowserThread::PostTask(
@@ skipping 27 matching lines @@
       base::Bind(&MockHostResolverCreator::DeleteMockHostResolverOnIOThread,
                  this));
   DCHECK(result);
 
   base::TimeDelta max_time = base::TimeDelta::FromSeconds(5);
   CHECK(resolver_event_.TimedWait(max_time));
 }
 
 void MockHostResolverCreator::DeleteMockHostResolverOnIOThread() {
   delete (mock_host_resolver_);
-  mock_host_resolver_ = NULL;
+  mock_host_resolver_ = nullptr;
   resolver_event_.Signal();
 }
 
 }  // namespace extensions