Remove JsonPrefStore pruning of empty values on write.

base/prefs/overlay_user_pref_store.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 "base/prefs/overlay_user_pref_store.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "base/values.h"
 
 OverlayUserPrefStore::OverlayUserPrefStore(
@@ skipping 75 matching lines @@
 void OverlayUserPrefStore::RemoveValue(const std::string& key) {
   if (!ShallBeStoredInOverlay(key)) {
     underlay_->RemoveValue(GetUnderlayKey(key));
     return;
   }
 
   if (overlay_.RemoveValue(key))
     ReportValueChanged(key);
 }
 
-void OverlayUserPrefStore::MarkNeedsEmptyValue(const std::string& key) {
-  if (!ShallBeStoredInOverlay(key))
-    underlay_->MarkNeedsEmptyValue(key);
-}
-
 bool OverlayUserPrefStore::ReadOnly() const {
   return false;
 }
 
 PersistentPrefStore::PrefReadError OverlayUserPrefStore::GetReadError() const {
   return PersistentPrefStore::PREF_READ_ERROR_NONE;
 }
 
 PersistentPrefStore::PrefReadError OverlayUserPrefStore::ReadPrefs() {
   // We do not read intentionally.
@@ skipping 62 matching lines @@
   NamesMap::const_iterator i =
       overlay_to_underlay_names_map_.find(overlay_key);
   return i != overlay_to_underlay_names_map_.end() ? i->second : overlay_key;
 }
 
 bool OverlayUserPrefStore::ShallBeStoredInOverlay(
     const std::string& key) const {
   return overlay_to_underlay_names_map_.find(key) !=
       overlay_to_underlay_names_map_.end();
 }