[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 54b00f3506d41f3f114ebfb022abf5ac6b577916..3b630e9b67ae1dc7ff633d6d286d1c02dc29fcd8 100644
--- a/public/web/WebWidget.h
+++ b/public/web/WebWidget.h
@@ -138,6 +138,9 @@ public:
     // compositor thread.
     virtual void applyScrollAndScale(const WebSize& scrollDelta, float scaleFactor) { }
 
+    // Records draw events for the Performance Timeline.
+    virtual void recordDrawTiming(int64_t RectId, const WebVector<std::pair<int, double> >& draws) { }
+
     // Called to inform the WebWidget that mouse capture was lost.
     virtual void mouseCaptureLost() { }