DevTools: Remove unused variables. Disallow unused variables with eslint

third_party/WebKit/Source/devtools/front_end/network/NetworkLogView.js

 /*
  * Copyright (C) 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2008, 2009 Anthony Ricaud <rik@webkit.org>
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 778 matching lines @@
   _refresh() {
     this._needsRefresh = false;
 
     if (this._refreshRequestId) {
       this.element.window().cancelAnimationFrame(this._refreshRequestId);
       delete this._refreshRequestId;
     }
 
     this.removeAllNodeHighlights();
 
-    var oldBoundary = this.calculator().boundary();
     this._timeCalculator.updateBoundariesForEventTime(this._mainRequestLoadTime);
     this._durationCalculator.updateBoundariesForEventTime(this._mainRequestLoadTime);
     this._timeCalculator.updateBoundariesForEventTime(this._mainRequestDOMContentLoadedTime);
     this._durationCalculator.updateBoundariesForEventTime(this._mainRequestDOMContentLoadedTime);
 
     var dataGrid = this._dataGrid;
     var rootNode = dataGrid.rootNode();
     /** @type {!Array<!Network.NetworkDataGridNode> } */
     var nodesToInsert = [];
     /** @type {!Array<!Network.NetworkDataGridNode> } */
@@ skipping 900 matching lines @@
   Running: 'running',
   FromCache: 'from-cache'
 };
 
 /** @type {!Array<string>} */
 Network.NetworkLogView._searchKeys =
     Object.keys(Network.NetworkLogView.FilterType).map(key => Network.NetworkLogView.FilterType[key]);
 
 /** @typedef {function(!SDK.NetworkRequest): boolean} */
 Network.NetworkLogView.Filter;