Remove uses of const in distiller javascript

components/dom_distiller/core/javascript/dom_distiller_viewer.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 function addToPage(html) {
   var div = document.createElement('div');
   div.innerHTML = html;
   document.getElementById('content').appendChild(div);
   fillYouTubePlaceholders();
 }
@@ skipping 186 matching lines @@
   var clampedScale = 1;
 
   var lastSpan;
   var lastClientMid;
 
   var scale = 1;
   var shiftX;
   var shiftY;
 
   // The zooming speed relative to pinching speed.
-  const FONT_SCALE_MULTIPLIER = 0.5;
-  const MIN_SPAN_LENGTH = 20;
+  var FONT_SCALE_MULTIPLIER = 0.5;
+  var MIN_SPAN_LENGTH = 20;
 
   // The font size is guaranteed to be in px.
   var baseSize =
       parseFloat(getComputedStyle(document.documentElement).fontSize);
 
   var refreshTransform = function() {
     var slowedScale = Math.exp(Math.log(scale) * FONT_SCALE_MULTIPLIER);
     clampedScale = Math.max(0.4, Math.min(2.5, fontSizeAnchor * slowedScale));
 
     // Use "fake" 3D transform so that the layer is not repainted.
@@ skipping 143 matching lines @@
         shiftY: shiftY
       };
     }
   };
 }());
 
 window.addEventListener('touchstart', pincher.handleTouchStart, false);
 window.addEventListener('touchmove', pincher.handleTouchMove, false);
 window.addEventListener('touchend', pincher.handleTouchEnd, false);
 window.addEventListener('touchcancel', pincher.handleTouchCancel, false);