Fix lint error in TimelinePanel.js due to 'energy' variable.

Source/devtools/front_end/TimelinePanel.js

 /*
  * Copyright (C) 2012 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 912 matching lines @@
         aggregatedStats["idle"] = Math.max(0, endTime - startTime - aggregatedTotal);
 
         var fragment = document.createDocumentFragment();
         fragment.appendChild(WebInspector.TimelineUIUtils.generatePieChart(aggregatedStats));
         var startOffset = startTime - this._model.minimumRecordTime();
         var endOffset = endTime - this._model.minimumRecordTime();
         var title = WebInspector.UIString("%s \u2013 %s", Number.millisToString(startOffset), Number.millisToString(endOffset));
 
         if (Capabilities.canProfilePower) {
             var powerOverview = /** @type {!WebInspector.TimelinePowerOverview} */ (this._viewsForMode(WebInspector.TimelinePanel.Mode.Power).overviewView);
-            energy = powerOverview.calculateEnergy(startTime, endTime);
+            var energy = powerOverview.calculateEnergy(startTime, endTime);
             title += WebInspector.UIString("  Energy: %.2f Joules", energy);
         }
         this._detailsView.setContent(title, fragment);
     },
 
     /**
      * @param {?WebInspector.TimelineModel.Record} record
      */
     selectRecord: function(record)
     {
@@ skipping 275 matching lines @@
      * @param {!WebInspector.TimelineModel.Record} record
      * @return {boolean}
      */
     accept: function(record)
     {
         return !this._hiddenRecords[record.type];
     },
 
     __proto__: WebInspector.TimelineModel.Filter.prototype
 }