MD Settings: make Subresource Filter exceptions a read-only-list

chrome/browser/resources/settings/privacy_page/privacy_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
 <link rel="import" href="chrome://resources/cr_elements/policy/cr_policy_vars_css.html">
 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/cr/ui/focus_without_ink.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
@@ skipping 395 matching lines @@
       <template is="dom-if" if="[[enableSafeBrowsingSubresourceFilter_]]"
           no-search>
         <template is="dom-if" route-path="/content/subresourceFilter" no-search>
           <settings-subpage page-title="$i18n{siteSettingsSubresourceFilter}">
             <category-default-setting
                 category="{{ContentSettingsTypes.SUBRESOURCE_FILTER}}"
                 toggle-off-label="$i18n{siteSettingsSubresourceFilterAllow}"
                 toggle-on-label="$i18n{siteSettingsSubresourceFilterBlock}">
             </category-default-setting>
             <category-setting-exceptions
-                category="{{ContentSettingsTypes.SUBRESOURCE_FILTER}}">
+                category="{{ContentSettingsTypes.SUBRESOURCE_FILTER}}"
+                read-only-list>
             </category-setting-exceptions>
           </settings-subpage>
        </template>
      </template>
      <template is="dom-if" route-path="/content/unsandboxedPlugins" no-search>
         <settings-subpage page-title="$i18n{siteSettingsUnsandboxedPlugins}">
           <category-default-setting
               toggle-off-label="$i18n{siteSettingsUnsandboxedPluginsBlock}"
               toggle-on-label=
                   "$i18n{siteSettingsUnsandboxedPluginsAskRecommended}"
@@ skipping 67 matching lines @@
                 category="{{ContentSettingsTypes.PROTECTED_CONTENT}}">
             </category-setting-exceptions>
           </template>
 </if>
         </settings-subpage>
       </template>
     </settings-animated-pages>
   </template>
   <script src="privacy_page.js"></script>
 </dom-module>