Remove PersistentPrefStore::MarkNeedsEmptyValue.

chrome/browser/prefs/pref_service.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 "chrome/browser/prefs/pref_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/file_path.h"
@@ skipping 295 matching lines @@
 
   // The main code path takes ownership, but most don't. We'll be safe.
   scoped_ptr<Value> scoped_value(default_value);
 
   CHECK(!FindPreference(path)) << "Tried to register duplicate pref " << path;
 
   base::Value::Type orig_type = default_value->GetType();
   DCHECK(orig_type != Value::TYPE_NULL && orig_type != Value::TYPE_BINARY) <<
          "invalid preference type: " << orig_type;
 
-  // For ListValue and DictionaryValue with non empty default, empty value
-  // for |path| needs to be persisted in |user_pref_store_|. So that
-  // non empty default is not used when user sets an empty ListValue or
-  // DictionaryValue.
-  bool needs_empty_value = false;
-  if (orig_type == base::Value::TYPE_LIST) {
-    const base::ListValue* list = NULL;
-    if (default_value->GetAsList(&list) && !list->empty())
-      needs_empty_value = true;
-  } else if (orig_type == base::Value::TYPE_DICTIONARY) {
-    const base::DictionaryValue* dict = NULL;
-    if (default_value->GetAsDictionary(&dict) && !dict->empty())
-      needs_empty_value = true;
-  }
-  if (needs_empty_value)
-    user_pref_store_->MarkNeedsEmptyValue(path);
-
   // Hand off ownership.
   default_store_->SetDefaultValue(path, scoped_value.release());
 }
 
 void PrefService::UnregisterPreference(const char* path) {
   DCHECK(CalledOnValidThread());
 
   PreferenceMap::iterator it = prefs_map_.find(path);
   CHECK(it != prefs_map_.end()) << "Trying to unregister an unregistered pref: "
                                 << path;
@@ skipping 224 matching lines @@
   const Value* found_value = NULL;
   if (pref_value_store_->GetValue(path, type, &found_value)) {
     DCHECK(found_value->IsType(type));
     return found_value;
   }
 
   // Every registered preference has at least a default value.
   NOTREACHED() << "no valid value found for registered pref " << path;
   return NULL;
 }