Unload the ScopedGaiaAuthExtension asynchronously.

chrome/browser/extensions/signin/gaia_auth_extension_loader.h

 // Copyright 2013 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_EXTENSIONS_SIGNIN_GAIA_AUTH_EXTENSION_LOADER_H_
 #define CHROME_BROWSER_EXTENSIONS_SIGNIN_GAIA_AUTH_EXTENSION_LOADER_H_
 
 #include <map>
 #include <string>
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "extensions/browser/browser_context_keyed_api_factory.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
 
 const char kGaiaAuthExtensionId[] = "mfffpogegjflfpflabcdkioaeobkgjik";
 const char kGaiaAuthExtensionOrigin[] =
       "chrome-extension://mfffpogegjflfpflabcdkioaeobkgjik";
 
 // Manages and registers the gaia auth extension with the extension system.
 class GaiaAuthExtensionLoader : public BrowserContextKeyedAPI {
  public:
   explicit GaiaAuthExtensionLoader(content::BrowserContext* context);
   ~GaiaAuthExtensionLoader() override;
 
   // Load the gaia auth extension if the extension is not loaded yet.
   void LoadIfNeeded();
   // Unload the gaia auth extension if no pending reference.
   void UnloadIfNeeded();
+  void UnloadIfNeededAsync();
 
   // Add a string data for gaia auth extension. Returns an ID that
   // could be used to get the data. All strings are cleared when gaia auth
   // is unloaded.
   int AddData(const std::string& data);
 
   // Get data for the given ID. Returns true if the data is found and
   // its value is copied to |data|. Otherwise, returns false.
   bool GetData(int data_id, std::string* data);
 
@@ skipping 14 matching lines @@
     return "GaiaAuthExtensionLoader";
   }
   static const bool kServiceRedirectedInIncognito = true;
 
   content::BrowserContext* browser_context_;
   int load_count_;
 
   int last_data_id_;
   std::map<int, std::string> data_;
 
+  base::WeakPtrFactory<GaiaAuthExtensionLoader> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(GaiaAuthExtensionLoader);
 };
 
 } // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_SIGNIN_GAIA_AUTH_EXTENSION_LOADER_H_