Timeline: show white overlay till page being reloaded paints

third_party/WebKit/Source/devtools/front_end/timeline_model/TimelineModel.js

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1635 matching lines @@
      */
     didPaint: function(paintEvent)
     {
         this._didPaint = true;
 
         // If a paint doesn't have a corresponding graphics layer id, it paints
         // into its parent so add an effectivePaintId to these events.
         var layerId = paintEvent.args["data"]["layerId"];
         if (layerId)
             this._lastPaintWithLayer = paintEvent;
-        if (!this._lastPaintWithLayer) {
-            console.error("Failed to find a paint container for a paint event.");
+        // Quietly discard top-level paints without layerId, as these are likely
+        // to come from overlay.
+        if (!this._lastPaintWithLayer)
             return;
-        }
 
         var effectivePaintId = this._lastPaintWithLayer.args["data"]["nodeId"];
         var paintFrameId = paintEvent.args["data"]["frame"];
         var types = [WebInspector.TimelineModel.RecordType.StyleRecalcInvalidationTracking,
             WebInspector.TimelineModel.RecordType.LayoutInvalidationTracking,
             WebInspector.TimelineModel.RecordType.PaintInvalidationTracking,
             WebInspector.TimelineModel.RecordType.ScrollInvalidationTracking];
         for (var invalidation of this._invalidationsOfTypes(types)) {
             if (invalidation.paintId === effectivePaintId)
                 this._addInvalidationToEvent(paintEvent, paintFrameId, invalidation);
@@ skipping 108 matching lines @@
         if (!id)
             return;
         /** @type {!Map<string, !WebInspector.TracingModel.Event>|undefined} */
         var initiatorMap = this._initiatorByType.get(initiatorType);
         if (isInitiator)
             initiatorMap.set(id, event);
         else
             event.initiator = initiatorMap.get(id) || null;
     }
 }