Timeline: show white overlay till page being reloaded paints

third_party/WebKit/LayoutTests/http/tests/inspector/timeline-test.js

 function wrapCallFunctionForTimeline(f)
 {
     var script = document.createElement("script");
     script.textContent = "(" + f.toString() + ")()\n//# sourceURL=wrapCallFunctionForTimeline.js";
     document.body.appendChild(script);
 }
 
 var initialize_Timeline = function() {
 
 InspectorTest.preloadPanel("timeline");
@@ skipping 71 matching lines @@
 }
 
 InspectorTest.invokeWithTracing = function(functionName, callback, additionalCategories, enableJSSampling)
 {
     var categories = "-*,disabled-by-default-devtools.timeline*,devtools.timeline," + WebInspector.TracingModel.TopLevelEventCategory;
     if (additionalCategories)
         categories += "," + additionalCategories;
     var timelinePanel = WebInspector.panels.timeline;
     var timelineController = InspectorTest.timelineController();
     timelinePanel._timelineController = timelineController;
-    timelineController._startRecordingWithCategories(categories, enableJSSampling, tracingStarted);
+    timelineController._startRecordingWithCategories(categories, enableJSSampling, undefined, tracingStarted);
 
     function tracingStarted()
     {
         InspectorTest.invokePageFunctionAsync(functionName, onPageActionsDone);
     }
 
     function onPageActionsDone()
     {
         InspectorTest.addSniffer(WebInspector.panels.timeline, "loadingComplete", callback)
         timelineController.stopRecording();
@@ skipping 367 matching lines @@
         if (!--count) {
             callback();
             return;
         }
         if (window.testRunner)
             testRunner.capturePixelsAsyncThen(requestAnimationFrame.bind(window, makeFrame));
         else
             window.requestAnimationFrame(makeFrame);
     }
 }