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

third_party/WebKit/Source/devtools/front_end/timeline/CountersGraph.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 85 matching lines @@
 
   /**
    * @override
    * @return {!UI.Widget}
    */
   view() {
     return this;
   }
 
   /**
+   * @protected
+   * @return {!TimelineModel.TimelineModel}
+   */
+  model() {
+    return this._model;
+  }
+
+  /**
    * @override
    */
   dispose() {
   }
 
   /**
    * @override
    */
   reset() {
     for (var i = 0; i < this._counters.length; ++i) {
@@ skipping 471 matching lines @@
   /**
    * @override
    * @return {number}
    */
   boundarySpan() {
     return this._maximumBoundary - this._minimumBoundary;
   }
 };
 
 Timeline.CounterGraphCalculator._minWidth = 5;