base: Add three helper functions to Values API.

chrome/browser/ui/webui/options/cookies_view_handler.cc

Index: chrome/browser/ui/webui/options/cookies_view_handler.cc
diff --git a/chrome/browser/ui/webui/options/cookies_view_handler.cc b/chrome/browser/ui/webui/options/cookies_view_handler.cc
index 536391fe3db8db7eba6a1ddda1014563ef3be0ee..8c6cb42aa5a9cf3628b54619fd37fdb6c56f4071 100644
--- a/chrome/browser/ui/webui/options/cookies_view_handler.cc
+++ b/chrome/browser/ui/webui/options/cookies_view_handler.cc
@@ -102,7 +102,7 @@ void CookiesViewHandler::TreeNodesAdded(ui::TreeModel* model,
 
   ListValue args;
   args.Append(parent == cookies_tree_model_->GetRoot() ?
-      Value::CreateNullValue() :
+      base::NullValue() :
       Value::CreateStringValue(
           cookies_tree_model_util::GetTreeNodeId(parent_node)));
   args.Append(Value::CreateIntegerValue(start));
@@ -120,7 +120,7 @@ void CookiesViewHandler::TreeNodesRemoved(ui::TreeModel* model,
 
   ListValue args;
   args.Append(parent == cookies_tree_model_->GetRoot() ?
-      Value::CreateNullValue() :
+      base::NullValue() :
       Value::CreateStringValue(cookies_tree_model_util::GetTreeNodeId(
           cookies_tree_model_->AsNode(parent))));
   args.Append(Value::CreateIntegerValue(start));
@@ -208,7 +208,7 @@ void CookiesViewHandler::SendChildren(CookieTreeNode* parent) {
 
   ListValue args;
   args.Append(parent == cookies_tree_model_->GetRoot() ?
-      Value::CreateNullValue() :
+      base::NullValue() :
       Value::CreateStringValue(cookies_tree_model_util::GetTreeNodeId(parent)));
   args.Append(children);