Nicely handle OnBeforeUnloads with guest and lock mode.

chrome/browser/ui/unload_controller.cc

 // 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.
 
 #include "chrome/browser/ui/unload_controller.h"
 
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/devtools/devtools_window.h"
 #include "chrome/browser/ui/browser.h"
@@ skipping 282 matching lines @@
       // If there's a devtools window attached to |web_contents|,
       // we would like devtools to call its own beforeunload handlers first,
       // and then call beforeunload handlers for |web_contents|.
       // See DevToolsWindow::InterceptPageBeforeUnload for details.
       if (!DevToolsWindow::InterceptPageBeforeUnload(web_contents))
         web_contents->DispatchBeforeUnload(false);
     } else {
       ClearUnloadState(web_contents, true);
     }
   } else if (is_calling_before_unload_handlers()) {
-    on_close_confirmed_.Run(true);
+    base::Callback<void(bool)> on_close_confirmed = on_close_confirmed_;
+    if (tabs_needing_unload_fired_.empty())
+      on_close_confirmed_.Reset();

[Peter Kasting, 2014/08/28 18:46:13]

Clearly order is important here; add comments explaining the control flow and
why we need to reset the member before running the callback.

[Mike Lerman, 2014/08/29 18:02:21]

Done.

+    on_close_confirmed.Run(true);
   } else if (!tabs_needing_unload_fired_.empty()) {
     // We've finished firing all beforeunload events and can proceed with unload
     // events.
     // TODO(ojan): We should add a call to browser_shutdown::OnShutdownStarting
     // somewhere around here so that we have accurate measurements of shutdown
     // time.
     // TODO(ojan): We can probably fire all the unload events in parallel and
     // get a perf benefit from that in the cases where the tab hangs in it's
     // unload handler or takes a long time to page in.
     content::WebContents* web_contents = *(tabs_needing_unload_fired_.begin());
@@ skipping 38 matching lines @@
     } else {
       base::MessageLoop::current()->PostTask(
           FROM_HERE,
           base::Bind(&UnloadController::ProcessPendingTabs,
                      weak_factory_.GetWeakPtr()));
     }
   }
 }
 
 }  // namespace chrome