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..830df64ccc6a94d3d4dc865602f81305798501e6 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;
+}
+
 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;
+  virtual void ForwardKeyboardEventWithLatencyInfo(
+      const NativeWebKeyboardEvent& key_event,
+      const ui::LatencyInfo& latency_info) = 0;
   virtual void ForwardGestureEvent(
       const blink::WebGestureEvent& gesture_event) = 0;