IDL: Add support for [TreatNullAs=EmptyString]

Source/bindings/core/v8/custom/V8InspectorFrontendHostCustom.cpp

 /*
  * Copyright (C) 2007-2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 62 matching lines @@
         if (typeString == "separator") {
             ContextMenuItem item(ContextMenuItem(SeparatorType,
                 ContextMenuItemCustomTagNoAction,
                 String()));
             menu.appendItem(item);
         } else if (typeString == "subMenu" && subItems->IsArray()) {
             ContextMenu subMenu;
             v8::Local<v8::Array> subItemsArray = v8::Local<v8::Array>::Cast(subItems);
             if (!populateContextMenuItems(subItemsArray, subMenu, isolate))
                 return false;
-            TOSTRING_DEFAULT(V8StringResource<WithNullCheck>, labelString, label, false);
+            TOSTRING_DEFAULT(V8StringResource<TreatNullAsNullString>, labelString, label, false);
             ContextMenuItem item(SubmenuType,
                 ContextMenuItemCustomTagNoAction,
                 labelString,
                 &subMenu);
             menu.appendItem(item);
         } else {
             ContextMenuAction typedId = static_cast<ContextMenuAction>(ContextMenuItemBaseCustomTag + id->ToInt32()->Value());
-            TOSTRING_DEFAULT(V8StringResource<WithNullCheck>, labelString, label, false);
+            TOSTRING_DEFAULT(V8StringResource<TreatNullAsNullString>, labelString, label, false);
             ContextMenuItem menuItem((typeString == "checkbox" ? CheckableActionType : ActionType), typedId, labelString);
             if (checked->IsBoolean())
                 menuItem.setChecked(checked->ToBoolean()->Value());
             if (enabled->IsBoolean())
                 menuItem.setEnabled(enabled->ToBoolean()->Value());
             menu.appendItem(menuItem);
         }
     }
     return true;
 }
@@ skipping 36 matching lines @@
     histogramEnumeration("DevTools.ActionTaken", info, 100);
 }
 
 void V8InspectorFrontendHost::recordPanelShownMethodCustom(const v8::FunctionCallbackInfo<v8::Value>& info)
 {
     histogramEnumeration("DevTools.PanelShown", info, 20);
 }
 
 } // namespace WebCore