[HBD] Update MD SiteSettingsHandler to support 3 modes.

chrome/browser/resources/settings/site_settings/site_settings_category.js

Index: chrome/browser/resources/settings/site_settings/site_settings_category.js
diff --git a/chrome/browser/resources/settings/site_settings/site_settings_category.js b/chrome/browser/resources/settings/site_settings/site_settings_category.js
index c1aa1baa373cc1c4eb9a2766fba1a57dcb5ead6c..67506803ee94af2d546c06d7058eb75b4b60e592 100644
--- a/chrome/browser/resources/settings/site_settings/site_settings_category.js
+++ b/chrome/browser/resources/settings/site_settings/site_settings_category.js
@@ -110,8 +110,12 @@ Polymer({
   onCategoryChanged_: function() {
     settings.SiteSettingsPrefsBrowserProxyImpl.getInstance()
         .getDefaultValueForContentType(
-            this.category).then(function(enabled) {
-              this.categoryEnabled = enabled;
+            this.category).then(function(setting) {
+              // FullScreen is Allow vs. Ask.
+              this.categoryEnabled =
+                  this.category == settings.ContentSettingsTypes.FULLSCREEN ?
+                      setting != settings.PermissionValues.ASK :
+                      setting != settings.PermissionValues.BLOCK;
             }.bind(this));
   },
 });