Hide BrowsingInstance from all but SiteInstance, as intended by design.

chrome/browser/extensions/extension_process_manager.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_EXTENSIONS_EXTENSION_PROCESS_MANAGER_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PROCESS_MANAGER_H_
 #pragma once
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "content/public/common/view_type.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class Browser;
-class BrowsingInstance;
 class Extension;
 class ExtensionHost;
 class GURL;
 class Profile;
 class RenderViewHost;
 class SiteInstance;
 
 // Manages dynamic state of running Chromium extensions. There is one instance
 // of this class per Profile. OTR Profiles have a separate instance that keeps
 // track of split-mode extensions only.
@@ skipping 80 matching lines @@
                        const content::NotificationDetails& details) OVERRIDE;
 
   content::NotificationRegistrar registrar_;
 
   // The set of all ExtensionHosts managed by this process manager.
   ExtensionHostSet all_hosts_;
 
   // The set of running viewless background extensions.
   ExtensionHostSet background_hosts_;
 
-  // The BrowsingInstance shared by all extensions in this profile.  This
-  // controls process grouping.
-  scoped_refptr<BrowsingInstance> browsing_instance_;
+  // A SiteInstance related to the SiteInstance for all extensions in
+  // this profile.  We create it in such a way that a new
+  // browsing instance is created.  This controls process grouping.
+  scoped_refptr<SiteInstance> site_instance_;
 
  private:
   // Contains all extension-related RenderViewHost instances for all extensions.
   typedef std::set<RenderViewHost*> RenderViewHostSet;
   RenderViewHostSet all_extension_views_;
 
   // Close the given |host| iff it's a background page.
   void CloseBackgroundHost(ExtensionHost* host);
 
   // Excludes background page.
   bool HasVisibleViews(const std::string& extension_id);
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionProcessManager);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PROCESS_MANAGER_H_