Remove JsonPrefStore pruning of empty values on write.

base/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 "base/prefs/pref_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
@@ skipping 279 matching lines @@
   DCHECK(CalledOnValidThread());
   // Lookup the preference in the default store.
   const base::Value* value = NULL;
   if (!pref_registry_->defaults()->GetValue(path, &value)) {
     NOTREACHED() << "Default value missing for pref: " << path;
     return NULL;
   }
   return value;
 }
 
-void PrefService::MarkUserStoreNeedsEmptyValue(const std::string& key) const {
-  user_pref_store_->MarkNeedsEmptyValue(key);
-}
-
 const base::ListValue* PrefService::GetList(const char* path) const {
   DCHECK(CalledOnValidThread());
 
   const base::Value* value = GetPreferenceValue(path);
   if (!value) {
     NOTREACHED() << "Trying to read an unregistered pref: " << path;
     return NULL;
   }
   if (value->GetType() != base::Value::TYPE_LIST) {
     NOTREACHED();
@@ skipping 28 matching lines @@
 
 // TODO(joi): Once MarkNeedsEmptyValue is gone, we can probably
 // completely get rid of this method. There will be one difference in
 // semantics; currently all registered preferences are stored right
 // away in the prefs_map_, if we remove this they would be stored only
 // opportunistically.
 void PrefService::AddRegisteredPreference(const char* path,
                                           base::Value* default_value) {
   DCHECK(CalledOnValidThread());
 
-  // 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;
-  base::Value::Type orig_type = default_value->GetType();
-  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);
+  //REMOVE?

[Mattias Nissler (ping if slow), 2013/11/22 08:03:38]

Yes, as well as PrefService::AddInitialPreferences and
PrefRegistry::SetRegistrationCallback.

[gab, 2013/11/22 23:24:21]

Hmmm interesting that I didn't get a PRESUBMIT check when uploading this... I
usually put comments with no space as notes to myself to be handled before
upload... somehow this made it up despite my intention of cleaning this up after
merging.

Thanks for clarifying what to remove, done.

 }
 
 void PrefService::ClearPref(const char* path) {
   DCHECK(CalledOnValidThread());
 
   const Preference* pref = FindPreference(path);
   if (!pref) {
     NOTREACHED() << "Trying to clear an unregistered pref: " << path;
     return;
   }
@@ skipping 215 matching lines @@
       DCHECK(found_value->IsType(default_type));
       return found_value;
     } else {
       // Every registered preference has at least a default value.
       NOTREACHED() << "no valid value found for registered pref " << path;
     }
   }
 
   return NULL;
 }