Track plugin input event latency

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 38dae3a51138205165ff259e8e1058fc122f24bd..e5c7453666184f83553ad96288e7a4054d3ca3b4 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -389,6 +389,7 @@ RenderWidget::RenderWidget(blink::WebPopupType popup_type,
       screen_info_(screen_info),
       device_scale_factor_(screen_info_.deviceScaleFactor),
       is_threaded_compositing_enabled_(false),
+      current_event_latency_info_(NULL),
       next_output_surface_id_(0),
 #if defined(OS_ANDROID)
       text_field_is_dirty_(false),
@@ -917,6 +918,9 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
     return;
   }
 
+  base::AutoReset<const ui::LatencyInfo*> resetter(&current_event_latency_info_,
+                                                   &latency_info);
+
   base::TimeTicks start_time;
   if (base::TimeTicks::IsHighResNowFastAndReliable())
     start_time = base::TimeTicks::HighResNow();