Implement a poor man's PostAfterStartupTask() function.

chrome/browser/chrome_content_browser_client.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROME_CONTENT_BROWSER_CLIENT_H_
 #define CHROME_BROWSER_CHROME_CONTENT_BROWSER_CLIENT_H_
 
 #include <set>
 #include <string>
 #include <utility>
@@ skipping 36 matching lines @@
   ~ChromeContentBrowserClient() override;
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // Notification that the application locale has changed. This allows us to
   // update our I/O thread cache of this value.
   static void SetApplicationLocale(const std::string& locale);
 
   content::BrowserMainParts* CreateBrowserMainParts(
       const content::MainFunctionParams& parameters) override;
+  content::AfterStartupTaskPoster* GetAfterStartupTaskPoster() override;
   std::string GetStoragePartitionIdForSite(
       content::BrowserContext* browser_context,
       const GURL& site) override;
   bool IsValidStoragePartitionId(content::BrowserContext* browser_context,
                                  const std::string& partition_id) override;
   void GetStoragePartitionConfigForSite(
       content::BrowserContext* browser_context,
       const GURL& site,
       bool can_be_default,
       std::string* partition_domain,
@@ skipping 281 matching lines @@
   std::vector<ChromeContentBrowserClientParts*> extra_parts_;
 
   base::WeakPtrFactory<ChromeContentBrowserClient> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeContentBrowserClient);
 };
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_CHROME_CONTENT_BROWSER_CLIENT_H_