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

extensions/browser/value_store/value_store_frontend.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/value_store/value_store_frontend.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "content/public/browser/browser_thread.h"
 #include "extensions/browser/value_store/leveldb_value_store.h"
 
 using content::BrowserThread;
 
 class ValueStoreFrontend::Backend : public base::RefCountedThreadSafe<Backend> {
  public:
-  Backend() : storage_(NULL) {}
+  Backend() : storage_(nullptr) {}
 
   void Init(const base::FilePath& db_path) {
     DCHECK_CURRENTLY_ON(BrowserThread::FILE);
     DCHECK(!storage_);
     TRACE_EVENT0("ValueStoreFrontend::Backend", "Init");
     db_path_ = db_path;
     storage_ = new LeveldbValueStore(db_path);
   }
 
   // This variant is useful for testing (using a mock ValueStore).
@@ skipping 109 matching lines @@
                  backend_, key, base::Passed(&value)));
 }
 
 void ValueStoreFrontend::Remove(const std::string& key) {
   DCHECK(CalledOnValidThread());
 
   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
       base::Bind(&ValueStoreFrontend::Backend::Remove,
                  backend_, key));
 }