Disable install of new default_apps for existing users

chrome/browser/extensions/external_provider_impl.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTERNAL_PROVIDER_IMPL_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTERNAL_PROVIDER_IMPL_H_
 
 #include <string>
 
 #include "chrome/browser/extensions/external_provider_interface.h"
@@ skipping 57 matching lines @@
   static const char kExternalVersion[];
   static const char kExternalUpdateUrl[];
   static const char kSupportedLocales[];
   static const char kIsBookmarkApp[];
 
   void set_auto_acknowledge(bool auto_acknowledge) {
     auto_acknowledge_ = auto_acknowledge;
   }
 
  private:
+  // Returns true if the app was a default app in Chrome 22.
+  static bool IsOldDefaultApp(const std::string& extension_id);
+
   // Location for external extensions that are provided by this provider from
   // local crx files.
   const Extension::Location crx_location_;
 
   // Location for external extensions that are provided by this provider from
   // update URLs.
   const Extension::Location download_location_;
 
   // Weak pointer to the object that consumes the external extensions.
   // This is zeroed out by: ServiceShutdown()
@@ skipping 17 matching lines @@
   // Whether loaded extensions should be automatically acknowledged, so that
   // the user doesn't see an alert about them.
   bool auto_acknowledge_;
 
   DISALLOW_COPY_AND_ASSIGN(ExternalProviderImpl);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTERNAL_PROVIDER_IMPL_H_