PlzNavigate: cancel any navigations if DispatchBeforeUnload is called (other than for starting a ...

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 56a7f1792c6bbe24465b54ca417b3a8d2edae688..34e252e72fbcf20334bfd04ad92da63984fa8a45 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -2332,6 +2332,12 @@ void RenderFrameHostImpl::DispatchBeforeUnload(bool for_navigation,
                                                bool is_reload) {
   DCHECK(for_navigation || !is_reload);
 
+  if (IsBrowserSideNavigationEnabled() && !for_navigation) {
+    // Cancel any pending navigations, to avoid their navigation commit/fail
+    // event from wiping out the is_waiting_for_beforeunload_ack_ state.
+    frame_tree_node_->ResetNavigationRequest(false);

[nasko, 2016/10/05 21:25:17]

If the beforeunload handler stops the tab from closing though, that means that
the tab will stay around and the navigation is cancelled. Seems strange
behavior, but I just tested it and it looks like this is how it works now :(.

+  }
+
   // TODO(creis): Support beforeunload on subframes.  For now just pretend that
   // the handler ran and allowed the navigation to proceed.
   if (!ShouldDispatchBeforeUnload()) {