[not for review] Add Draw entries to window Performance Timeline

public/web/WebWidget.h

Index: public/web/WebWidget.h
diff --git a/public/web/WebWidget.h b/public/web/WebWidget.h
index 149e98356e253b38acd64e09c1e2971084011947..6da29b53d7a03ad1948a5a65d9d51f4f06b577d2 100644
--- a/public/web/WebWidget.h
+++ b/public/web/WebWidget.h
@@ -150,6 +150,14 @@ public:
         float scaleFactor,
         float topControlsDelta) { }
 
+    enum smoothnessTimingEventType {
+        CommitEvent,
+        CompositeEvent,
+    };
+
+    // Records composite or commit events for the Performance Timeline.
+    virtual void recordSmoothnessTimingEvent(smoothnessTimingEventType eventType, int64_t RectId, const WebVector<std::pair<int, double> >& events) { }
+
     // Called to inform the WebWidget that mouse capture was lost.
     virtual void mouseCaptureLost() { }