Fix: tabs slow to response to beforeunload are closed prematurely.

content/browser/frame_host/render_frame_host_impl.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_impl.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 2106 matching lines @@
     // Increment the in-flight event count, to ensure that input events won't
     // cancel the timeout timer.
     render_view_host_->GetWidget()->increment_in_flight_event_count();
     render_view_host_->GetWidget()->StartHangMonitorTimeout(
         TimeDelta::FromMilliseconds(RenderViewHostImpl::kUnloadTimeoutMS));
     send_before_unload_start_time_ = base::TimeTicks::Now();
     Send(new FrameMsg_BeforeUnload(routing_id_));
   }
 }
 
+void RenderFrameHostImpl::SimulateBeforeUnloadAck() {
+  DCHECK(is_waiting_for_beforeunload_ack_);
+  base::TimeTicks approx_renderer_start_time = send_before_unload_start_time_;
+  OnBeforeUnloadACK(true, approx_renderer_start_time, base::TimeTicks::Now());
+}
+
 bool RenderFrameHostImpl::ShouldDispatchBeforeUnload() {
   // TODO(creis): Support beforeunload on subframes.
   return !GetParent() && IsRenderFrameLive();
 }
 
 void RenderFrameHostImpl::UpdateOpener() {
   // This frame (the frame whose opener is being updated) might not have had
   // proxies for the new opener chain in its SiteInstance.  Make sure they
   // exist.
   if (frame_tree_node_->opener()) {
@@ skipping 627 matching lines @@
   // handler after it's destroyed so it can't run after the RFHI is destroyed.
   web_bluetooth_service_->SetClientConnectionErrorHandler(base::Bind(
       &RenderFrameHostImpl::DeleteWebBluetoothService, base::Unretained(this)));
 }
 
 void RenderFrameHostImpl::DeleteWebBluetoothService() {
   web_bluetooth_service_.reset();
 }
 
 }  // namespace content