Quickly close tabs/window with long-running unload handlers.

chrome/browser/ui/unload_detached_handler.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_UI_UNLOAD_DETACHED_HANDLER_H_
+#define CHROME_BROWSER_UI_UNLOAD_DETACHED_HANDLER_H_
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/memory/scoped_vector.h"
+
+class TabStripModel;
+
+namespace content {
+class WebContents;
+}
+
+namespace chrome {
+
+class UnloadController;
+
+typedef base::Callback<void(void)> TabsClosedCallback;
+
+// UnloadDetachedHandler is used to close tabs quickly, http://crbug.com/142458.
+//   - Allows unload handlers to run in the background.
+//   - Comes into play after the beforeunload handlers (if any) have run.
+//   - Does not close the tabs; it holds tabs while they are closed.
+//
+// TODO(slamm): Support closes that destroy the browser: last tab close, window.
+//     http://crbug.com/156896
+// TODO(slamm): Hide unload time from the user for cross-process navigations.
+//     http://crbug.com/156958
+class UnloadDetachedHandler {
+ public:
+  explicit UnloadDetachedHandler(const TabsClosedCallback& callback);
+  ~UnloadDetachedHandler();
+
+  // Returns true if is succeeds.
+  bool DetachWebContents(TabStripModel* tab_strip_model,
+                         content::WebContents* web_contents);
+  bool HasTabs();
+
+ private:
+  class WebContentsDelegateImpl;
+
+  // Clean-up when the tab finishes closing.
+  void Destroy(WebContentsDelegateImpl* delegate);
+
+  const TabsClosedCallback tabs_closed_callback_;
+
+  ScopedVector<WebContentsDelegateImpl> delegates_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(UnloadDetachedHandler);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_UI_UNLOAD_DETACHED_HANDLER_H_