DevTools: Remove unused variables. Disallow unused variables with eslint

third_party/WebKit/Source/devtools/front_end/timeline/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 1059 matching lines @@
     this._revealTimeRange(frame.startTime, frame.endTime);
     this.select(Timeline.TimelineSelection.fromFrame(frame));
     return true;
   }
 
   /**
    * @param {!SDK.PaintProfilerSnapshot} snapshot
    */
   _showSnapshotInPaintProfiler(snapshot) {
     var paintProfilerView = this._paintProfilerView();
-    var hasProfileData = paintProfilerView.setSnapshot(snapshot);
+    paintProfilerView.setSnapshot(snapshot);
     if (!this._detailsView.hasTab(Timeline.TimelinePanel.DetailsTab.PaintProfiler)) {
       this._detailsView.appendTab(
           Timeline.TimelinePanel.DetailsTab.PaintProfiler, Common.UIString('Paint Profiler'), paintProfilerView,
           undefined, undefined, true);
     }
     this._detailsView.selectTab(Timeline.TimelinePanel.DetailsTab.PaintProfiler, true);
   }
 
   /**
    * @param {!SDK.TracingModel.Event} event
@@ skipping 879 matching lines @@
   }
 
   /**
    * @override
    * @param {!SDK.Target} target
    */
   targetRemoved(target) {
     this._targets.remove(target, true);
   }
 };