DevTools: enable private field checks as a part of compilation.

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

 /*
  * Copyright (C) 2013 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 510 matching lines @@
 
   /**
    * @override
    * @param {number} x
    * @return {!Promise<?Element>}
    */
   popoverElementPromise(x) {
     if (!this._filmStripModel.frames().length)
       return Promise.resolve(/** @type {?Element} */ (null));
 
-    var time = this._calculator.positionToTime(x);
+    var time = this.calculator().positionToTime(x);
     var frame = this._filmStripModel.frameByTimestamp(time);
     if (frame === this._lastFrame)
       return Promise.resolve(this._lastElement);
     var imagePromise = frame ? this._imageByFrame(frame) : Promise.resolve(this._emptyImage);
     return imagePromise.then(createFrameElement.bind(this));
 
     /**
      * @this {Timeline.TimelineFilmStripOverview}
      * @param {!HTMLImageElement} image
      * @return {?Element}
@@ skipping 237 matching lines @@
       counters[group] = this._quantDuration;
       this._callback(counters);
       interval -= this._quantDuration;
     }
     this._counters = [];
     this._counters[group] = interval;
     this._lastTime = time;
     this._remainder = this._quantDuration - interval;
   }
 };