display error message for empty distilled content

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';
-  updateLoadingIndicator(isLastPage);
-}
-
-// Maps JS Font Family to CSS class and then changes body class name.
-// CSS classes must agree with distilledpage.css.
-function useFontFamily(fontFamily) {
-  var cssClass;
-  if (fontFamily == "serif") {
-    cssClass = "serif";
-  } else if (fontFamily == "monospace") {
-    cssClass = "monospace";
-  } else {
-    cssClass = "sans-serif";
-  }
-  // Relies on the classname order of the body being Theme class, then Font
-  // Family class.
-  var themeClass = document.body.className.split(" ")[0];
-  document.body.className = themeClass + " " + cssClass;
-}
-
-// 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";
-  }
-  // Relies on the classname order of the body being Theme class, then Font
-  // Family class.
-  var fontFamilyClass = document.body.className.split(" ")[1];
-  document.body.className = cssClass + " " + fontFamilyClass;
-}
-
-var updateLoadingIndicator = function() {
-  var colors = ["red", "yellow", "green", "blue"];
-  return function(isLastPage) {
-    if (!isLastPage && typeof this.colorShuffle == "undefined") {
-      var loader = document.getElementById("loader");
-      if (loader) {
-        var colorIndex = -1;
-        this.colorShuffle = setInterval(function() {
-          colorIndex = (colorIndex + 1) % colors.length;
-          loader.className = colors[colorIndex];
-        }, 600);
-      }
-    } else if (isLastPage && typeof this.colorShuffle != "undefined") {
-      clearInterval(this.colorShuffle);
-    }
-  };
-}();