Observing DocumentTiming and sending data to RenderFrameImpl

public/web/WebFrameClient.h

Index: public/web/WebFrameClient.h
diff --git a/public/web/WebFrameClient.h b/public/web/WebFrameClient.h
index 7315757934077015dbc723a1cd926063178f1358..db5910bd65b2784b6db15515b85e8c451caca285 100644
--- a/public/web/WebFrameClient.h
+++ b/public/web/WebFrameClient.h
@@ -454,6 +454,9 @@ public:
     // A PingLoader was created, and a request dispatched to a URL.
     virtual void didDispatchPingLoader(WebLocalFrame*, const WebURL&) { }
 
+    // A performance timing event (e.g. first paint) occurred
+    virtual void didChangePerformanceTiming() { }
+
     // The loaders in this frame have been stopped.
     virtual void didAbortLoading(WebLocalFrame*) { }