Add Keyboard Latency UMA Metrics.

content/public/browser/render_widget_host.h

Index: content/public/browser/render_widget_host.h
diff --git a/content/public/browser/render_widget_host.h b/content/public/browser/render_widget_host.h
index f2f435042fce3725205731781410f8663a495ec1..89ce2175d4c4981ee234b3b85b3a253a01917dfc 100644
--- a/content/public/browser/render_widget_host.h
+++ b/content/public/browser/render_widget_host.h
@@ -25,6 +25,10 @@ class WebMouseEvent;
 class WebMouseWheelEvent;
 }
 
+namespace ui {
+class LatencyInfo;
+};

[sadrul, 2017/05/11 04:57:00]

Don't need the ; at the end.

[tdresser, 2017/05/11 18:55:55]

Done.

+
 namespace content {
 
 struct CursorInfo;
@@ -166,6 +170,9 @@ class CONTENT_EXPORT RenderWidgetHost : public IPC::Sender {
       const blink::WebMouseWheelEvent& wheel_event) = 0;
   virtual void ForwardKeyboardEvent(
       const NativeWebKeyboardEvent& key_event) = 0;

[sadrul, 2017/05/11 04:57:00]

Should you just add LatencyInfo here with a default value?

[tdresser, 2017/05/11 18:55:55]

Default arguments are banned on virtual functions.
https://google.github.io/styleguide/cppguide.html#Default_Arguments

+  virtual void ForwardKeyboardEventWithLatencyInfo(
+      const NativeWebKeyboardEvent& key_event,
+      const ui::LatencyInfo& latency_info) = 0;
   virtual void ForwardGestureEvent(
       const blink::WebGestureEvent& gesture_event) = 0;