Keep track in the browser of which frames have onunload and onbeforeunload handlers.

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/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ skipping 309 matching lines @@
   if (!tabs_needing_before_unload_fired_.empty()) {
     content::WebContents* web_contents =
         *(tabs_needing_before_unload_fired_.begin());
     // Null check render_view_host here as this gets called on a PostTask and
     // the tab's render_view_host may have been nulled out.
     if (web_contents->GetRenderViewHost()) {
       // 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();
+      if (!DevToolsWindow::InterceptPageBeforeUnload(web_contents)) {
+        if (web_contents->NeedToFireBeforeUnload()) {
+          web_contents->DispatchBeforeUnload();
+        } else {
+          ClearUnloadState(web_contents, true);
+        }
+      }
     } else {
       ClearUnloadState(web_contents, true);
     }
   } else if (is_calling_before_unload_handlers()) {
     base::Callback<void(bool)> on_close_confirmed = on_close_confirmed_;
     // Reset |on_close_confirmed_| in case the callback tests
     // |is_calling_before_unload_handlers()|, we want to return that calling
     // is complete.
     if (tabs_needing_unload_fired_.empty())
       on_close_confirmed_.Reset();
@@ skipping 52 matching lines @@
       if (weak_factory_.HasWeakPtrs())
         return;
       base::ThreadTaskRunnerHandle::Get()->PostTask(
           FROM_HERE, base::Bind(&UnloadController::ProcessPendingTabs,
                                 weak_factory_.GetWeakPtr(), false));
     }
   }
 }
 
 }  // namespace chrome