Use chrome_html structure for shared_resources and options2 page.

chrome/browser/resources/options2/options_page.css

 /* Copyright (c) 2012 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. */
 
 body {
   position: relative;
 }
 
 #main-content {
   bottom: 0;
@@ skipping 120 matching lines @@
 .main-page-banner .managed-prefs-gradient {
   -webkit-margin-end: 20px;
   -webkit-margin-start: 0;
   margin-bottom: 9px;
 }
 
 .managed-prefs-text {
   background-image: url('chrome://theme/IDR_MANAGED');
   background-position: 5px center;
   background-repeat: no-repeat;
+  background-size: 16px;
   display: block;
   line-height: 24px;
   padding-left: 26px;
 }
 
 .managed-prefs-banner.clickable:active .managed-prefs-text {
   background: -webkit-linear-gradient(rgb(250, 230, 145),
                                       rgb(255, 242, 183));
 }
 
@@ skipping 293 matching lines @@
   width: 16px;
 }
 
 .controlled-setting-indicator summary::-webkit-details-marker {
   display: none;
 }
 
 .controlled-setting-indicator[controlled-by='policy'] summary {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_MANDATORY_GRAY');
+  background-size: 16px;
 }
 
 .controlled-setting-indicator[controlled-by='policy'] summary:hover {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_MANDATORY');
+  background-size: 16px;
 }
 
 .controlled-setting-indicator[controlled-by='extension'] summary {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_EXTENSION_GRAY');
+  background-size: 16px;
 }
 
 .controlled-setting-indicator[controlled-by='extension'] summary:hover {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_EXTENSION');
+  background-size: 16px;
 }
 
 .controlled-setting-indicator[controlled-by='recommended'] summary {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_RECOMMENDED_GRAY');
+  background-size: 16px;
 }
 
 .controlled-setting-indicator[controlled-by='recommended'] summary:hover {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_RECOMMENDED');
+  background-size: 16px;
 }
 
 .controlled-setting-bubble {
   -webkit-margin-start: -20px;
   background-color: white;
   border: 1px solid #ccc;
   border-radius: 4px;
   box-shadow: 0 2px 2px #ddd;
   margin-top: 10px;
   padding: 10px;
@@ skipping 35 matching lines @@
   background-repeat: no-repeat;
   margin: 0;
   min-height: 32px;
   min-width: 200px;
 }
 
 .controlled-setting-indicator[controlled-by='policy']
     .controlled-setting-bubble-text {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_MANDATORY_LARGE');
+  background-size: 22px;
 }
 
 .controlled-setting-indicator[controlled-by='extension']
     .controlled-setting-bubble-text {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_EXTENSION_LARGE');
+  background-size: 22px;
 }
 
 .controlled-setting-indicator[controlled-by='recommended']
     .controlled-setting-bubble-text {
   background-image:
       url('chrome://theme/IDR_CONTROLLED_SETTING_RECOMMENDED_LARGE');
+  background-size: 22px;
 }
 
 html[dir='rtl'] .controlled-setting-bubble-text {
   background-position: right top;
 }
 
 .controlled-setting-bubble-action {
   padding: 0 !important;
 }