Removed NOTIFICATION_BROWSER_CLOSING notification

chrome/browser/ui/browser.cc

 // Copyright 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.
 
 #include "chrome/browser/ui/browser.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 728 matching lines @@
       TabRestoreServiceFactory::GetForProfile(profile());
 
 #if defined(USE_AURA)
   if (tab_restore_service && is_app() && !is_devtools())
     tab_restore_service->BrowserClosing(live_tab_context());
 #endif
 
   if (tab_restore_service && is_type_tabbed() && tab_strip_model_->count())
     tab_restore_service->BrowserClosing(live_tab_context());
 
+  BrowserList::NotifyBrowserCloseStarted(this);
+
   // TODO(sky): convert session/tab restore to use notification.
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_BROWSER_CLOSING,

[hashimoto, 2017/04/14 08:54:37]

How about moving this notification code to
BrowserList::NotifyBrowserCloseStarted?
The same goes for NOTIFICATION_BROWSER_CLOSE_CANCELLED in
fast_unload_controller.cc and unload_controller.cc.

[Alexey Seren, 2017/04/22 19:52:54]

Acknowledged.

       content::Source<Browser>(this),
       content::NotificationService::NoDetails());
 
   if (!IsFastTabUnloadEnabled())
     tab_strip_model_->CloseAllTabs();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // In-progress download termination handling:
 
@@ skipping 1787 matching lines @@
       BookmarkBar::DONT_ANIMATE_STATE_CHANGE);
 }
 
 bool Browser::ShouldHideUIForFullscreen() const {
   // Windows and GTK remove the browser controls in fullscreen, but Mac and Ash
   // keep the controls in a slide-down panel.
   return window_ && window_->ShouldHideUIForFullscreen();
 }
 
 bool Browser::ShouldStartShutdown() const {
-  return BrowserList::GetInstance()->size() <= 1;
+  DCHECK_GE(BrowserList::GetInstance()->size(),
+            BrowserList::GetInstance()->currently_closing_browsers_count());
+  // Start shutdown process only when closing the last browser.
+  return BrowserList::GetInstance()->size() ==
+         BrowserList::GetInstance()->currently_closing_browsers_count() + 1;

[hashimoto, 2017/04/14 08:54:37]

Sorry, I still don't understand why this change is needed.
This function is used only in Browser::OnWindowClosing(), and IIUC it eventually
returns true when closing the last Browser.

[Alexey Seren, 2017/04/22 19:52:54]

This fixes the races happened when two browsers are closing simultaneously. How
it can happen:
Suppose that we have already called Browser::OnWindowClosing() for the first
browser and lets suppose that Browser::OnWindowClosing() for the second browser
was called before the first browser was closed in BrowserList::RemoveBrowser().
In this case when calling OnWindowClosing() for the second browser we will have
BrowserList::GetInstance()->size() == 2.
So Browser::ShouldStartShutdown() will return false.

To fix this we need to keep track of currently closing browsers list.

[hashimoto, 2017/04/28 09:16:29]

Thank you for the explanation.
I don't think it's the right thing to do to return true from
ShouldStartShutdown() when the window close can be still cancelled.

ShouldStartShutdown's only user is Browser::OnWindowClosing().
Can't we stop calling browser_shutdown::OnShutdownStarting() in
Browser::OnWindowClosing(), and instead call
browser_shutdown::OnShutdownStarting() somewhere else when window close is
actually finished (or the last keep alive is released from the
KeepAliveRegistry)?

[Alexey Seren, 2017/05/03 17:19:44]

Actually we cannot cancel shutdown after we have entered
Browser::OnWindowClosing() once. This functionality was done by following CL:
https://codereview.chromium.org/2695233003
Ok, I will try to find right place for this.

 }
 
 bool Browser::MaybeCreateBackgroundContents(
     content::SiteInstance* source_site_instance,
     const GURL& opener_url,
     int32_t route_id,
     int32_t main_frame_route_id,
     int32_t main_frame_widget_route_id,
     const std::string& frame_name,
     const GURL& target_url,
@@ skipping 68 matching lines @@
     // new window later, thus we need to navigate the window now.
     if (contents) {
       contents->web_contents()->GetController().LoadURL(
           target_url, content::Referrer(), ui::PAGE_TRANSITION_LINK,
           std::string());  // No extra headers.
     }
   }
 
   return contents != NULL;
 }