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

content/browser/frame_host/render_frame_host_manager_unittest.cc

 // Copyright 2013 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 "content/browser/frame_host/render_frame_host_manager.h"
 
 #include <stdint.h>
 
 #include <tuple>
 #include <utility>
@@ skipping 1246 matching lines @@
   rfh1->GetSiteInstance()->IncrementActiveFrameCount();
 
   contents()->NavigateAndCommit(kUrl2);
   TestRenderFrameHost* rfh2 = main_test_rfh();
   rfh2->GetSiteInstance()->IncrementActiveFrameCount();
 
   // Now go back, but suppose the SwapOut_ACK isn't received.  This shouldn't
   // happen, but we have seen it when going back quickly across many entries
   // (http://crbug.com/93427).
   contents()->GetController().GoBack();
-  EXPECT_TRUE(rfh2->is_waiting_for_beforeunload_ack());

[nasko, 2017/03/29 23:31:26]

Why not set_has_beforeunload_handlers on rfh2? We already fudge some of the
state on rfh2 above anyway. 

[jam, 2017/03/30 14:53:22]

similar to my other reply, this isn't what the unit test is testing.

   contents()->GetMainFrame()->PrepareForCommit();
-  EXPECT_FALSE(rfh2->is_waiting_for_beforeunload_ack());
 
   // The back navigation commits.
   const NavigationEntry* entry1 = contents()->GetController().GetPendingEntry();
   contents()->GetPendingMainFrame()->SendNavigate(
       entry1->GetUniqueID(), false, entry1->GetURL());
   EXPECT_TRUE(rfh2->IsWaitingForUnloadACK());
   EXPECT_FALSE(rfh2->is_active());
 
   // We should be able to navigate forward.
   contents()->GetController().GoForward();
@@ skipping 597 matching lines @@
        CancelPendingProperlyDeletesOrSwaps) {
   const GURL kUrl1("http://www.google.com/");
   const GURL kUrl2("http://www.chromium.org/");
   RenderFrameHostImpl* pending_rfh = NULL;
   base::TimeTicks now = base::TimeTicks::Now();
 
   // Navigate to the first page.
   contents()->NavigateAndCommit(kUrl1);
   TestRenderFrameHost* rfh1 = main_test_rfh();
   EXPECT_TRUE(rfh1->is_active());
+  rfh1->set_has_beforeunload_handlers();
 
   // Navigate to a new site, starting a cross-site navigation.
   controller().LoadURL(
       kUrl2, Referrer(), ui::PAGE_TRANSITION_LINK, std::string());
   {
     pending_rfh = contents()->GetPendingMainFrame();
     RenderFrameDeletedObserver rfh_deleted_observer(pending_rfh);
 
     // Cancel the navigation by simulating a declined beforeunload dialog.
     contents()->GetMainFrame()->OnMessageReceived(
@@ skipping 1255 matching lines @@
   ASSERT_FALSE(delete_observer.deleted());
   EXPECT_FALSE(initial_rfh->is_active());
 
   // The initial RFH receives a DidStartProvisionalLoad IPC. It should not
   // create a NavigationHandle.
   initial_rfh->SimulateNavigationStart(kUrl3);
   EXPECT_FALSE(initial_rfh->navigation_handle());
 }
 
 }  // namespace content