Change infobar creation to use a public static Create() method on the infobar delegate classes.

chrome/browser/infobars/infobar_extension_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/infobars/infobar_extension_api.h"
 
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/values.h"
 #include "chrome/browser/api/infobars/confirm_infobar_delegate.h"
@@ skipping 46 matching lines @@
       &browser,
       NULL,
       &web_contents,
       NULL)) {
     error_ = extensions::ErrorUtils::FormatErrorMessage(
         extensions::tabs_constants::kTabNotFoundError,
         base::IntToString(tab_id));
     return false;
   }
 
-  InfoBarService* infobar_service =
-      InfoBarService::FromWebContents(web_contents);
-  infobar_service->AddInfoBar(
-      new ExtensionInfoBarDelegate(browser, infobar_service,
-                                   GetExtension(), url, height));
+  ExtensionInfoBarDelegate::Create(
+      InfoBarService::FromWebContents(web_contents), browser, GetExtension(),
+      url, height);
 
   // TODO(finnur): Return the actual DOMWindow object. Bug 26463.
   DCHECK(browser->extension_window_controller());
   SetResult(browser->extension_window_controller()->CreateWindowValue());
 
   return true;
 }