Theme Preferences for Distilled Pages

components/dom_distiller/content/resources/dom_distiller_viewer.js

 // Copyright 2014 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.
 
 function addToPage(html) {
   var div = document.createElement('div');
   div.innerHTML = html;
   document.getElementById('content').appendChild(div);
 }
 
 function showLoadingIndicator(isLastPage) {
   document.getElementById('loadingIndicator').className =
       isLastPage ? 'hidden' : 'visible';
-}
+}
+
+// Maps JS theme to CSS class and then changes body class name.
+// CSS classes must agree with distilledpage.css.
+function useTheme(theme) {
+  var cssClass;
+  if (theme == "sepia") {
+    cssClass = "sepia";
+  } else if (theme == "dark") {
+    cssClass = "dark";
+  } else {
+    cssClass = "light";
+  }
+  document.body.className = cssClass;
+}