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

components/sync/syncable/entry_kernel.cc

 // Copyright (c) 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.
 
 #include "components/sync/syncable/entry_kernel.h"
 
 #include <utility>
 
 #include "base/json/string_escape.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 206 matching lines @@
   for (EntryKernelMutationMap::const_iterator it = mutations.begin();
        it != mutations.end(); ++it) {
     list->Append(EntryKernelMutationToValue(it->second));
   }
   return list;
 }
 
 std::unique_ptr<base::DictionaryValue> EntryKernelMutationToValue(
     const EntryKernelMutation& mutation) {
   std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue());
-  dict->Set("original", mutation.original.ToValue(NULL));
-  dict->Set("mutated", mutation.mutated.ToValue(NULL));
+  dict->Set("original", mutation.original.ToValue(nullptr));
+  dict->Set("mutated", mutation.mutated.ToValue(nullptr));
   return dict;
 }
 
 std::ostream& operator<<(std::ostream& os, const EntryKernel& entry_kernel) {
   int i;
   EntryKernel* const kernel = const_cast<EntryKernel*>(&entry_kernel);
   for (i = BEGIN_FIELDS; i < INT64_FIELDS_END; ++i) {
     os << g_metas_columns[i].name << ": "
        << kernel->ref(static_cast<Int64Field>(i)) << ", ";
   }
@@ skipping 34 matching lines @@
   os << "TempFlags: ";
   for (; i < BIT_TEMPS_END; ++i) {
     if (kernel->ref(static_cast<BitTemp>(i)))
       os << "#" << i - BIT_TEMPS_BEGIN << ", ";
   }
   return os;
 }
 
 }  // namespace syncable
 }  // namespace syncer