Move unload handling off Browser onto its own class, UnloadController.

chrome/browser/ui/unload_controller.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_CONTROLLER_H_
+#define CHROME_BROWSER_UI_UNLOAD_CONTROLLER_H_
+#pragma once
+
+#include <set>
+
+#include "base/memory/weak_ptr.h"
+#include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+class Browser;
+class TabContents;
+class TabStripModel;
+
+namespace content {
+class NotificationSource;
+class NotifictaionDetails;
+class WebContents;
+}
+
+namespace chrome {
+
+class UnloadController : public content::NotificationObserver,
+                         public TabStripModelObserver {
+ public:
+  explicit UnloadController(Browser* browser);
+  virtual ~UnloadController();
+
+  // Returns true if |contents| can be cleanly closed. When |browser_| is being
+  // closed, this function will return false to indicate |contents| should not
+  // be cleanly closed, since the fast shutdown path will just kill its
+  // renderer.
+  bool CanCloseContents(content::WebContents* contents);
+
+  // Called when a BeforeUnload handler is fired for |contents|. |proceed|
+  // indicates the user's response to the Y/N BeforeUnload handler dialog. If
+  // this parameter is false, any pending attempt to close the whole browser
+  // will be canceled. Returns true if Unload handlers should be fired. When the
+  // |browser_| is being closed, Unload handlers for any particular WebContents
+  // will not be run until every WebContents being closed has a chance to run
+  // its BeforeUnloadHandler.
+  bool BeforeUnloadFired(content::WebContents* contents, bool proceed);
+
+  bool is_attempting_to_close_browser() const {
+    return is_attempting_to_close_browser_;
+  }
+
+  // Called in response to a request to close |browser_|'s window. Returns true
+  // when there are no remaining unload handlers to be run.
+  bool ShouldCloseWindow();
+
+  // Returns true if |browser_| has any tabs that have BeforeUnload handlers
+  // that have not been fired. This method is non-const because it builds a list
+  // of tabs that need their BeforeUnloadHandlers fired.
+  // TODO(beng): This seems like it could be private but it is used by
+  //             AreAllBrowsersCloseable() in application_lifetime.cc. It seems
+  //             very similar to ShouldCloseWindow() and some consolidation
+  //             could be pursued.
+  bool TabsNeedBeforeUnloadFired();
+
+ private:
+  typedef std::set<content::WebContents*> UnloadListenerSet;
+
+  // Overridden from content::NotificationObserver:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  // Overridden from TabStripModelObserver:
+  virtual void TabInsertedAt(TabContents* contents,
+                             int index,
+                             bool foreground) OVERRIDE;
+  virtual void TabDetachedAt(TabContents* contents, int index) OVERRIDE;
+  virtual void TabReplacedAt(TabStripModel* tab_strip_model,
+                             TabContents* old_contents,
+                             TabContents* new_contents,
+                             int index) OVERRIDE;
+  virtual void TabStripEmpty() OVERRIDE;
+
+  void TabAttachedImpl(TabContents* contents);
+  void TabDetachedImpl(TabContents* contents);
+
+  // Processes the next tab that needs it's beforeunload/unload event fired.
+  void ProcessPendingTabs();
+
+  // Whether we've completed firing all the tabs' beforeunload/unload events.
+  bool HasCompletedUnloadProcessing() const;
+
+  // Clears all the state associated with processing tabs' beforeunload/unload
+  // events since the user cancelled closing the window.
+  void CancelWindowClose();
+
+  // Removes |web_contents| from the passed |set|.
+  // Returns whether the tab was in the set in the first place.
+  bool RemoveFromSet(UnloadListenerSet* set,
+                     content::WebContents* web_contents);
+
+  // Cleans up state appropriately when we are trying to close the browser and
+  // the tab has finished firing its unload handler. We also use this in the
+  // cases where a tab crashes or hangs even if the beforeunload/unload haven't
+  // successfully fired. If |process_now| is true |ProcessPendingTabs| is
+  // invoked immediately, otherwise it is invoked after a delay (PostTask).
+  //
+  // Typically you'll want to pass in true for |process_now|. Passing in true
+  // may result in deleting |tab|. If you know that shouldn't happen (because of
+  // the state of the stack), pass in false.
+  void ClearUnloadState(content::WebContents* web_contents, bool process_now);
+
+  Browser* browser_;
+
+  content::NotificationRegistrar registrar_;
+
+  // Tracks tabs that need there beforeunload event fired before we can
+  // close the browser. Only gets populated when we try to close the browser.
+  UnloadListenerSet tabs_needing_before_unload_fired_;
+
+  // Tracks tabs that need there unload event fired before we can
+  // close the browser. Only gets populated when we try to close the browser.
+  UnloadListenerSet tabs_needing_unload_fired_;
+
+  // Whether we are processing the beforeunload and unload events of each tab
+  // in preparation for closing the browser. UnloadController owns this state
+  // rather than Browser because unload handlers are the only reason that a
+  // Browser window isn't just immediately closed.
+  bool is_attempting_to_close_browser_;
+
+  base::WeakPtrFactory<UnloadController> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(UnloadController);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_UI_UNLOAD_CONTROLLER_H_