Fix crash with --load-extension for extensions with plugins

chrome/browser/ui/extensions/extension_install_ui_default.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/ui/extensions/extension_install_ui_default.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ skipping 173 matching lines @@
   if (browser)
     web_contents = browser->tab_strip_model()->GetActiveWebContents();
   return new ExtensionInstallPrompt(web_contents);
 }
 
 // static
 ExtensionInstallPrompt* ExtensionInstallUI::CreateInstallPromptWithProfile(
     Profile* profile) {
   Browser* browser = chrome::FindLastActiveWithProfile(profile,
       chrome::GetActiveDesktop());
-  return CreateInstallPromptWithBrowser(browser);
+  if (browser)
+    return CreateInstallPromptWithBrowser(browser);
+  // No browser window is open yet. Create a free-standing dialog associated
+  // with |profile|.
+  return new ExtensionInstallPrompt(profile, NULL, NULL);
 }
 
 
 // ExtensionInstallUIDefault --------------------------------------------------
 
 ExtensionInstallUIDefault::ExtensionInstallUIDefault(Profile* profile)
     : ExtensionInstallUI(profile),
       previous_using_native_theme_(false),
       use_app_installed_bubble_(false) {
   // |profile| can be NULL during tests.
@@ skipping 79 matching lines @@
       browser->tab_strip_model()->GetActiveWebContents();
   if (!web_contents)
     return;
   ErrorInfoBarDelegate::Create(InfoBarService::FromWebContents(web_contents),
                                error);
 }
 
 void ExtensionInstallUIDefault::SetUseAppInstalledBubble(bool use_bubble) {
   use_app_installed_bubble_ = use_bubble;
 }