Refactor Material Design PDF Viewer toolbar into a single element

chrome/browser/resources/pdf/index-material.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. */
 
 @font-face {
   font-family: 'Roboto';
   font-style: normal;
   font-weight: 400;
   src: local('Roboto Regular'), local('Roboto-Regular'), url(chrome://resources/roboto/roboto.woff2) format('woff2');
   unicode-range: U+0460-052F, U+20B4, U+2DE0-2DFF, U+A640-A69F;
 }
 
 body {
   background-color: #eee;
   font-family: Roboto, 'Helvetica Neue', Helvetica, Arial;
   margin: 0;
 }
 
-core-toolbar {
-  background-color: transparent;
-  color: rgb(241, 241, 241);
-  font-size: 1.5em;
-  height: 56px;
-  padding-left: 1em;
-  padding-right: 1em;
-  z-index: 3;
-}
-
-#toolbar-shadow {
+viewer-pdf-toolbar {
   position: fixed;
   width: 100%;
   z-index: 4;
 }
 
-#progress-bar {
-  height: 56px;
-  position: absolute;
-  width: 100%;
-  z-index: 3;
-}
-
-paper-progress::shadow #activeProgress {
-  background-color: rgb(33, 150, 243);
-}
-
-paper-progress::shadow #progressContainer {
-  background-color: rgb(100, 181, 246);
-}
-
 #plugin {
   position: fixed;
   top: 56px;
   z-index: 1;
 }
 
 #sizer {
   position: absolute;
   z-index: 0;
 }
@@ skipping 15 matching lines @@
 
 viewer-error-screen {
   visibility: hidden;
   z-index: 2;
 }
 
 viewer-password-screen {
   visibility: hidden;
   z-index: 2;
 }