Issue 11428116 had to be reverted as it broke build due to a unused variable.

chrome/common/extensions/extension.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/common/extensions/extension.h"
 
 #include <ostream>
 
 #include "base/base64.h"
 #include "base/basictypes.h"
@@ skipping 1321 matching lines @@
 }
 
 bool Extension::is_hosted_app() const {
   return manifest()->is_hosted_app();
 }
 
 bool Extension::is_legacy_packaged_app() const {
   return manifest()->is_legacy_packaged_app();
 }
 
+bool Extension::is_extension() const {
+  return manifest()->is_extension();
+}
+
 bool Extension::can_be_incognito_enabled() const {
   return !is_platform_app();
 }
 
 bool Extension::is_theme() const {
   return manifest()->is_theme();
 }
 
 GURL Extension::GetBackgroundURL() const {
   if (background_scripts_.empty())
@@ skipping 2868 matching lines @@
 
 UpdatedExtensionPermissionsInfo::UpdatedExtensionPermissionsInfo(
     const Extension* extension,
     const PermissionSet* permissions,
     Reason reason)
     : reason(reason),
       extension(extension),
       permissions(permissions) {}
 
 }   // namespace extensions