Add a new top-level inspector timeline event for the PrePaint step

third_party/WebKit/Source/devtools/front_end/timeline/TimelineUIUtils.js

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel 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.
@@ skipping 60 matching lines @@
     eventStyles[recordTypes.Layout] =
         new Timeline.TimelineRecordStyle(Common.UIString('Layout'), categories['rendering']);
     eventStyles[recordTypes.PaintSetup] =
         new Timeline.TimelineRecordStyle(Common.UIString('Paint Setup'), categories['painting']);
     eventStyles[recordTypes.PaintImage] =
         new Timeline.TimelineRecordStyle(Common.UIString('Paint Image'), categories['painting'], true);
     eventStyles[recordTypes.UpdateLayer] =
         new Timeline.TimelineRecordStyle(Common.UIString('Update Layer'), categories['painting'], true);
     eventStyles[recordTypes.UpdateLayerTree] =
         new Timeline.TimelineRecordStyle(Common.UIString('Update Layer Tree'), categories['rendering']);
+    eventStyles[recordTypes.PreparePaint] =
+        new Timeline.TimelineRecordStyle(Common.UIString('Prepare Paint'), categories['painting']);
     eventStyles[recordTypes.Paint] = new Timeline.TimelineRecordStyle(Common.UIString('Paint'), categories['painting']);
     eventStyles[recordTypes.RasterTask] =
         new Timeline.TimelineRecordStyle(Common.UIString('Rasterize Paint'), categories['painting']);
     eventStyles[recordTypes.ScrollLayer] =
         new Timeline.TimelineRecordStyle(Common.UIString('Scroll'), categories['rendering']);
     eventStyles[recordTypes.CompositeLayers] =
         new Timeline.TimelineRecordStyle(Common.UIString('Composite Layers'), categories['painting']);
     eventStyles[recordTypes.ParseHTML] =
         new Timeline.TimelineRecordStyle(Common.UIString('Parse HTML'), categories['loading']);
     eventStyles[recordTypes.ParseAuthorStyleSheet] =
@@ skipping 2154 matching lines @@
   /**
    * @param {!SDK.TracingModel.Event} event
    * @param {string=} warningType
    */
   appendWarningRow(event, warningType) {
     var warning = Timeline.TimelineUIUtils.eventWarning(event, warningType);
     if (warning)
       this.appendElementRow(Common.UIString('Warning'), warning, true);
   }
 };