Cleanup/ Remove deprecated extension notification from ExtensionHost

chrome/browser/extensions/extension_view_host.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_EXTENSION_VIEW_HOST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_VIEW_HOST_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "components/web_modal/popup_manager.h"
 #include "components/web_modal/web_contents_modal_dialog_host.h"
 #include "components/web_modal/web_contents_modal_dialog_manager_delegate.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 #include "extensions/browser/extension_host.h"
 
 class Browser;
 
 namespace content {
 class SiteInstance;
 class WebContents;
 }
 
 namespace extensions {
 
 class ExtensionView;
 
 // The ExtensionHost for an extension that backs a view in the browser UI. For
 // example, this could be an extension popup or dialog, but not a background
 // page.
 // TODO(gbillock): See if we can remove WebContentsModalDialogManager here.
 class ExtensionViewHost
     : public ExtensionHost,
       public web_modal::WebContentsModalDialogManagerDelegate,
-      public web_modal::WebContentsModalDialogHost {
+      public web_modal::WebContentsModalDialogHost,
+      public content::NotificationObserver {
  public:
   ExtensionViewHost(const Extension* extension,
                     content::SiteInstance* site_instance,
                     const GURL& url,
                     ViewType host_type);
   ~ExtensionViewHost() override;
 
   ExtensionView* view() { return view_.get(); }
   const ExtensionView* view() const { return view_.get(); }
 
@@ skipping 77 matching lines @@
   // Observer to detect when the associated web contents is destroyed.
   class AssociatedWebContentsObserver;
   scoped_ptr<AssociatedWebContentsObserver> associated_web_contents_observer_;
 
   // Manage popups overlaying the WebContents in this EVH.
   // TODO(gbillock): should usually not be used -- instead use the parent
   // window's popup manager. Should only be used when the EVH is created without
   // a parent window.
   scoped_ptr<web_modal::PopupManager> popup_manager_;
 
+  content::NotificationRegistrar registrar_;
+
   DISALLOW_COPY_AND_ASSIGN(ExtensionViewHost);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_VIEW_HOST_H_