[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 d0e12437890840de7d3f096cb11941719c0c1f65..eebc5b9b3850bbf2b2b3328e5048e0957a56588c 100644
--- a/public/web/WebWidget.h
+++ b/public/web/WebWidget.h
@@ -144,6 +144,9 @@ 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() { }