[Sync] Replacing NULL with nullptr in code and null in comments for components/sync/

components/sync/base/cryptographer.h

 // Copyright 2012 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.
 
 #ifndef COMPONENTS_SYNC_BASE_CRYPTOGRAPHER_H_
 #define COMPONENTS_SYNC_BASE_CRYPTOGRAPHER_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 143 matching lines @@
   void SetDefaultKey(const std::string& key_name);
 
   bool is_initialized() const {
     return !nigoris_.empty() && !default_nigori_name_.empty();
   }
 
   // Returns whether this Cryptographer is ready to encrypt and decrypt data.
   bool is_ready() const { return is_initialized() && !has_pending_keys(); }
 
   // Returns whether there is a pending set of keys that needs to be decrypted.
-  bool has_pending_keys() const { return NULL != pending_keys_.get(); }
+  bool has_pending_keys() const { return nullptr != pending_keys_.get(); }
 
   // Obtain a token that can be provided on construction to a future
   // Cryptographer instance to bootstrap itself.  Returns false if such a token
   // can't be created (i.e. if this Cryptograhper doesn't have valid keys).
   bool GetBootstrapToken(std::string* token) const;
 
   Encryptor* encryptor() const { return encryptor_; }
 
   // Returns true if |keybag| is decryptable and either is a subset of nigoris_
   // and/or has a different default key.
@@ skipping 35 matching lines @@
   std::string default_nigori_name_;
 
   std::unique_ptr<sync_pb::EncryptedData> pending_keys_;
 
   DISALLOW_ASSIGN(Cryptographer);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_BASE_CRYPTOGRAPHER_H_