[Coverity] Extension pointer can be null in the if clause, so we should rely on extension_id

chrome/browser/extensions/api/developer_private/developer_private_api.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/browser/extensions/api/developer_private/developer_private_api.h"
 
 #include "apps/app_load_service.h"
 #include "apps/app_restore_service.h"
 #include "apps/saved_files_service.h"
 #include "apps/shell_window.h"
@@ skipping 635 matching lines @@
   std::string extension_id = params->item_id;
 
   ExtensionSystem* system = ExtensionSystem::Get(profile());
   ManagementPolicy* management_policy = system->management_policy();
   ExtensionService* service = profile()->GetExtensionService();
 
   const Extension* extension = service->GetInstalledExtension(extension_id);
   if (!extension ||
       !management_policy->UserMayModifySettings(extension, NULL)) {
     LOG(ERROR) << "Attempt to enable an extension that is non-usermanagable "
-               "was made. Extension id: " << extension->id();
+               "was made. Extension id: " << extension_id.c_str();
     return false;
   }
 
   if (params->enable) {
     ExtensionPrefs* prefs = service->extension_prefs();
     if (prefs->DidExtensionEscalatePermissions(extension_id)) {
       ShellWindowRegistry* registry = ShellWindowRegistry::Get(profile());
       CHECK(registry);
       ShellWindow* shell_window = registry->GetShellWindowForRenderViewHost(
           render_view_host());
@@ skipping 611 matching lines @@
   return true;
 }
 
 DeveloperPrivateIsProfileManagedFunction::
     ~DeveloperPrivateIsProfileManagedFunction() {
 }
 
 } // namespace api
 
 } // namespace extensions