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

chrome/browser/ui/extensions/extension_install_ui_default.cc

Index: chrome/browser/ui/extensions/extension_install_ui_default.cc
diff --git a/chrome/browser/ui/extensions/extension_install_ui_default.cc b/chrome/browser/ui/extensions/extension_install_ui_default.cc
index d72036c1774c97fb1a5bc1c254cc720fdf91048c..6fa1d4a5e1bff8739511736822e38f04de6bc3d1 100644
--- a/chrome/browser/ui/extensions/extension_install_ui_default.cc
+++ b/chrome/browser/ui/extensions/extension_install_ui_default.cc
@@ -191,7 +191,11 @@ 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);
 }