Update colors of material design PDF viewer.

chrome/browser/resources/pdf/elements/viewer-zoom-selector/viewer-zoom-selector.css

 /* Copyright 2015 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. */
 
 :host {
   bottom: 0;
   padding: 24px;
   position: fixed;
   right: 0;
   z-index: 3;
 }
 
 #zoom-buttons {
   display: inline-block;
 }
 
 #slider {
   display: inline-block;
   margin-bottom: 0.8em;
   margin-right: 2em;
   overflow: visible;
 }
 
 #main-zoom {
-  background-color: rgb(33, 150, 243);
+  background-color: rgb(27, 168, 243);
   display: block;
   margin: auto;
   margin-top: 2em;
   overflow: visible;
 }
 
 #fit-to-width-button {
   display: block;
   margin: auto;
   margin-top: 2em;
   overflow: visible;
 }
 
 #fit-to-page-button {
   display: block;
   margin: auto;
   overflow: visible;
 }