<webview>, <appview> and <extensionoptions> can run in a detached state.

extensions/browser/guest_view/app_view/app_view_guest.h

 // Copyright 2014 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 EXTENSIONS_BROWSER_GUEST_VIEW_APP_VIEW_APP_VIEW_GUEST_H_
 #define EXTENSIONS_BROWSER_GUEST_VIEW_APP_VIEW_APP_VIEW_GUEST_H_
 
 #include "base/id_map.h"
 #include "extensions/browser/extension_function_dispatcher.h"
 #include "extensions/browser/guest_view/app_view/app_view_guest_delegate.h"
@@ skipping 34 matching lines @@
   bool HandleContextMenu(const content::ContextMenuParams& params) override;
   void RequestMediaAccessPermission(
       content::WebContents* web_contents,
       const content::MediaStreamRequest& request,
       const content::MediaResponseCallback& callback) override;
   bool CheckMediaAccessPermission(content::WebContents* web_contents,
                                   const GURL& security_origin,
                                   content::MediaStreamType type) override;
 
   // GuestViewBase implementation.
+  bool CanRunInDetachedState() const override;
+  void CreateWebContents(const base::DictionaryValue& create_params,
+                         const WebContentsCreatedCallback& callback) override;
+  void DidInitialize(const base::DictionaryValue& create_params) override;
   const char* GetAPINamespace() const override;
   int GetTaskPrefix() const override;
-  void CreateWebContents(const base::DictionaryValue& create_params,
-                         const WebContentsCreatedCallback& callback) override;
-  void DidAttachToEmbedder() override;
-  void DidInitialize(const base::DictionaryValue& create_params) override;
 
   // Sets the AppDelegate for this guest.
   void SetAppDelegateForTest(AppDelegate* delegate);
 
  private:
   AppViewGuest(content::WebContents* owner_web_contents, int guest_instance_id);
 
   ~AppViewGuest() override;
 
   void OnRequest(const ExtensionHostMsg_Request_Params& params);
@@ skipping 15 matching lines @@
   // This is used to ensure pending tasks will not fire after this object is
   // destroyed.
   base::WeakPtrFactory<AppViewGuest> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AppViewGuest);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_GUEST_VIEW_APP_VIEW_APP_VIEW_GUEST_H_