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 ba8879e29e799a1abaf1afbc54fcbd61f699093f..4ca4b6169cd42f41391c2d0d346b191607c3fb98 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -385,6 +385,7 @@ 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),
@@ -932,6 +933,8 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
     return;
   }
 
+  current_event_latency_info_ = &latency_info;

[piman, 2014/04/25 01:59:43]

I fear potential early outs (some could be added later). This function is huge.
Can you use an AutoReset<LatencyInfo> for RAII goodness?

[Yufeng Shen (Slow to review), 2014/04/25 20:42:42]

Done.

+
   base::TimeTicks start_time;
   if (base::TimeTicks::IsHighResNowFastAndReliable())
     start_time = base::TimeTicks::HighResNow();
@@ -1116,6 +1119,7 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
 #endif
 
   TRACE_EVENT_SYNTHETIC_DELAY_END("blink.HandleInputEvent");
+  current_event_latency_info_ = NULL;
   handling_input_event_ = false;
 
   if (!prevent_default) {