Move beforeunload hang timer duties to its own timer.

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 4afec65e2be43a227764516076b2ccd59f26758f..f2e115f5c46f29470f74c02d7322063fce291b92 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -2111,7 +2111,7 @@ InputEventAckState RenderWidgetHostImpl::FilterInputEvent(
 
 void RenderWidgetHostImpl::IncrementInFlightEventCount(
     blink::WebInputEvent::Type event_type) {
-  increment_in_flight_event_count();
+  ++in_flight_event_count_;
   if (!is_hidden_) {
     StartHangMonitorTimeout(
         hung_renderer_delay_, event_type,
@@ -2121,7 +2121,8 @@ void RenderWidgetHostImpl::IncrementInFlightEventCount(
 
 void RenderWidgetHostImpl::DecrementInFlightEventCount(
     InputEventAckSource ack_source) {
-  if (decrement_in_flight_event_count() <= 0) {
+  --in_flight_event_count_;
+  if (in_flight_event_count_ <= 0) {
     // Cancel pending hung renderer checks since the renderer is responsive.
     StopHangMonitorTimeout();
   } else {