DevTools: Remove unused variables. Disallow unused variables with eslint

third_party/WebKit/Source/devtools/front_end/components/Spectrum.js

 /*
  * Copyright (C) 2011 Brian Grinstead 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
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 258 matching lines @@
         shadow.style.background = palette.colors[i];
         shadow = colorElement.createChild('div', 'spectrum-palette-color spectrum-palette-color-shadow');
         shadow.style.background = palette.colors[i];
         colorElement.title = Common.UIString(palette.colors[i] + '. Long-click to show alternate shades.');
         new UI.LongClickController(colorElement, this._showLightnessShades.bind(this, colorElement, palette.colors[i]));
       }
       this._paletteContainer.appendChild(colorElement);
     }
     this._paletteContainerMutable = palette.mutable;
 
-    var numItems = palette.colors.length;
-    if (palette.mutable)
-      numItems++;
     if (palette.mutable) {
       this._paletteContainer.appendChild(this._addColorToolbar.element);
       this._paletteContainer.appendChild(this._deleteIconToolbar.element);
     } else {
       this._addColorToolbar.element.remove();
       this._deleteIconToolbar.element.remove();
     }
 
     this._togglePalettePanel(false);
     this._focus();
@@ skipping 756 matching lines @@
   '#607D8B':
       ['#ECEFF1', '#CFD8DC', '#B0BEC5', '#90A4AE', '#78909C', '#607D8B', '#546E7A', '#455A64', '#37474F', '#263238']
 };
 
 Components.Spectrum.MaterialPalette = {
   title: 'Material',
   mutable: false,
   matchUserFormat: true,
   colors: Object.keys(Components.Spectrum.MaterialPaletteShades)
 };