Test run for https://codereview.chromium.org/2725993002/ with the timer intentionally broken.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index 8388af1bad8925ce675338110d87c801e8c1f58a..7a15dea549c747ce2d613556f1345b24b9ce0765 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -38,6 +38,7 @@
 #include "content/browser/gpu/gpu_process_host.h"
 #include "content/browser/host_zoom_map_impl.h"
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
+#include "content/browser/renderer_host/input/timeout_monitor.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host_delegate.h"
 #include "content/browser/renderer_host/render_view_host_delegate_view.h"
@@ -229,6 +230,9 @@ RenderViewHostImpl::RenderViewHostImpl(
                    base::Unretained(ResourceDispatcherHostImpl::Get()),
                    GetProcess()->GetID(), GetRoutingID()));
   }
+
+  close_timeout_.reset(new TimeoutMonitor(base::Bind(
+      &RenderViewHostImpl::ClosePageTimeout, weak_factory_.GetWeakPtr())));
 }
 
 RenderViewHostImpl::~RenderViewHostImpl() {
@@ -575,10 +579,6 @@ WebPreferences RenderViewHostImpl::ComputeWebkitPrefs() {
 
 void RenderViewHostImpl::ClosePage() {
   is_waiting_for_close_ack_ = true;
-  GetWidget()->StartHangMonitorTimeout(
-      TimeDelta::FromMilliseconds(kUnloadTimeoutMS),
-      blink::WebInputEvent::Undefined,
-      RendererUnresponsiveType::RENDERER_UNRESPONSIVE_CLOSE_PAGE);
 
   bool is_javascript_dialog_showing = delegate_->IsJavaScriptDialogShowing();
 
@@ -586,10 +586,8 @@ void RenderViewHostImpl::ClosePage() {
   // close event because it is known unresponsive, waiting for the reply from
   // the dialog.
   if (IsRenderViewLive() && !is_javascript_dialog_showing) {
-    // Since we are sending an IPC message to the renderer, increase the event
-    // count to prevent the hang monitor timeout from being stopped by input
-    // event acknowledgments.
-    GetWidget()->increment_in_flight_event_count();
+    // Intentionally broken timer.
+    // close_timeout_->Start(TimeDelta::FromMilliseconds(kUnloadTimeoutMS));
 
     // TODO(creis): Should this be moved to Shutdown?  It may not be called for
     // RenderViewHosts that have been swapped out.
@@ -607,7 +605,7 @@ void RenderViewHostImpl::ClosePage() {
 }
 
 void RenderViewHostImpl::ClosePageIgnoringUnloadEvents() {
-  GetWidget()->StopHangMonitorTimeout();
+  close_timeout_->Stop();
   is_waiting_for_close_ack_ = false;
 
   sudden_termination_allowed_ = true;
@@ -853,7 +851,6 @@ void RenderViewHostImpl::OnTakeFocus(bool reverse) {
 }
 
 void RenderViewHostImpl::OnClosePageACK() {
-  GetWidget()->decrement_in_flight_event_count();
   ClosePageIgnoringUnloadEvents();
 }
 
@@ -959,4 +956,16 @@ void RenderViewHostImpl::RenderViewReady() {
   delegate_->RenderViewReady(this);
 }
 
+void RenderViewHostImpl::ClosePageTimeout() {
+  if (delegate_->ShouldIgnoreUnresponsiveRenderer())
+    return;
+
+  UMA_HISTOGRAM_ENUMERATION(
+      "ChildProcess.HangRendererType",
+      RendererUnresponsiveType::RENDERER_UNRESPONSIVE_CLOSE_PAGE,
+      RendererUnresponsiveType::RENDERER_UNRESPONSIVE_MAX);
+
+  ClosePageIgnoringUnloadEvents();
+}
+
 }  // namespace content