Make show_dialog_callback optional in ExtensionInstallPrompt

chrome/browser/extensions/crx_installer.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/crx_installer.h"
 
 #include <map>
 #include <set>
 
 #include "base/bind.h"
@@ skipping 88 matching lines @@
       apps_require_extension_mime_type_(false),
       allow_silent_install_(false),
       install_cause_(extension_misc::INSTALL_CAUSE_UNSET),
       creation_flags_(Extension::NO_FLAGS),
       off_store_install_allow_reason_(OffStoreInstallDisallowed),
       did_handle_successfully_(true),
       record_oauth2_grant_(false),
       error_on_unsupported_requirements_(false),
       requirements_checker_(new extensions::RequirementsChecker()),
       has_requirement_errors_(false) {
-  show_dialog_callback_ =
-      ExtensionInstallPrompt::GetDefaultShowDialogCallback();
   if (!approval)
     return;
 
   CHECK(profile_->IsSameProfile(approval->profile));
   if (client_) {
     client_->install_ui()->SetUseAppInstalledBubble(
         approval->use_app_installed_bubble);
     client_->install_ui()->SetSkipPostInstallUI(approval->skip_post_install_ui);
   }
 
@@ skipping 533 matching lines @@
   // is problematic because they don't know anything about the
   // extension before it is unpacked, so they cannot filter based
   // on the extension.
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_CRX_INSTALLER_DONE,
       content::Source<CrxInstaller>(this),
       content::Details<const Extension>(extension));
 }
 
 }  // namespace extensions