Consistent content placement method for dom-distiller

components/dom_distiller/core/viewer.cc

Index: components/dom_distiller/core/viewer.cc
diff --git a/components/dom_distiller/core/viewer.cc b/components/dom_distiller/core/viewer.cc
index 00e05ca447e2a8665bdffd1376ef9a5a590d91c5..4e74d2b4d789b5e223c468005b1ac98ec2fb1eb8 100644
--- a/components/dom_distiller/core/viewer.cc
+++ b/components/dom_distiller/core/viewer.cc
@@ -90,9 +90,12 @@ const std::string GetFontCssClass(DistilledPagePrefs::FontFamily font_family) {
   return kSansSerifCssClass;
 }
 
-void EnsureNonEmptyTitleAndContent(std::string* title, std::string* content) {
+void EnsureNonEmptyTitle(std::string* title) {
   if (title->empty())
     *title = l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_TITLE);
+}
+
+void EnsureNonEmptyContent(std::string* content) {
   UMA_HISTOGRAM_BOOLEAN("DomDistiller.PageHasDistilledData", !content->empty());
   if (content->empty()) {
     *content = l10n_util::GetStringUTF8(
@@ -103,7 +106,6 @@ void EnsureNonEmptyTitleAndContent(std::string* title, std::string* content) {
 std::string ReplaceHtmlTemplateValues(
     const std::string& title,
     const std::string& textDirection,
-    const std::string& content,
     const std::string& loading_indicator_class,
     const std::string& original_url,
     const DistilledPagePrefs::Theme theme,
@@ -117,12 +119,11 @@ std::string ReplaceHtmlTemplateValues(
   substitutions.push_back(kViewerJsPath);                                 // $3
   substitutions.push_back(GetThemeCssClass(theme) + " " +
                           GetFontCssClass(font_family));                  // $4
-  substitutions.push_back(content);                                       // $5
-  substitutions.push_back(loading_indicator_class);                       // $6
-  substitutions.push_back(original_url);                                  // $7
+  substitutions.push_back(loading_indicator_class);                       // $5
+  substitutions.push_back(original_url);                                  // $6
   substitutions.push_back(
-      l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_VIEW_ORIGINAL));  // $8
-  substitutions.push_back(textDirection);                                 // $9
+      l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_VIEW_ORIGINAL));  // $7
+  substitutions.push_back(textDirection);                                 // $8
   return ReplaceStringPlaceholders(html_template, substitutions, NULL);
 }
 
@@ -136,6 +137,7 @@ const std::string GetUnsafeIncrementalDistilledPageJs(
   std::string output;
   base::StringValue value(page_proto->html());
   base::JSONWriter::Write(&value, &output);
+  EnsureNonEmptyContent(&output);
   std::string page_update("addToPage(");
   page_update += output + ");";
   return page_update + GetToggleLoadingIndicatorJs(
@@ -143,6 +145,16 @@ const std::string GetUnsafeIncrementalDistilledPageJs(
 
 }
 
+const std::string GetErrorPageJs() {
+  base::StringValue value(l10n_util::GetStringUTF8(
+      IDS_DOM_DISTILLER_VIEWER_FAILED_TO_FIND_ARTICLE_CONTENT));
+  std::string output;
+  base::JSONWriter::Write(&value, &output);
+  std::string page_update("addToPage(");
+  page_update += output + ");";
+  return page_update;
+}
+
 const std::string GetToggleLoadingIndicatorJs(const bool is_last_page) {
   if (is_last_page)
     return "showLoadingIndicator(true);";
@@ -150,51 +162,42 @@ const std::string GetToggleLoadingIndicatorJs(const bool is_last_page) {
     return "showLoadingIndicator(false);";
 }
 
-const std::string GetUnsafePartialArticleHtml(
+const std::string GetUnsafeArticleTemplateHtml(
     const DistilledPageProto* page_proto,
     const DistilledPagePrefs::Theme theme,
     const DistilledPagePrefs::FontFamily font_family) {
   DCHECK(page_proto);
+
   std::string title = net::EscapeForHTML(page_proto->title());
-  std::ostringstream unsafe_output_stream;
-  unsafe_output_stream << page_proto->html();
-  std::string unsafe_article_html = unsafe_output_stream.str();
-  EnsureNonEmptyTitleAndContent(&title, &unsafe_article_html);
+
+  EnsureNonEmptyTitle(&title);
+
+  std::string text_direction = page_proto->text_direction();
   std::string original_url = page_proto->url();
-  return ReplaceHtmlTemplateValues(
-      title, page_proto->text_direction(), unsafe_article_html, "visible",
-      original_url, theme, font_family);
+
+  return ReplaceHtmlTemplateValues(title, text_direction, "hidden",
+                                   original_url, theme, font_family);
 }
 
-const std::string GetUnsafeArticleHtml(
-    const DistilledArticleProto* article_proto,
-    const DistilledPagePrefs::Theme theme,
-    const DistilledPagePrefs::FontFamily font_family) {
+const std::string GetUnsafeArticleContentJs(
+    const DistilledArticleProto* article_proto) {
   DCHECK(article_proto);
-  std::string title;
-  std::string unsafe_article_html;
-  std::string text_direction = "";
-  if (article_proto->has_title() && article_proto->pages_size() > 0 &&
-      article_proto->pages(0).has_html()) {
-    title = net::EscapeForHTML(article_proto->title());
-    std::ostringstream unsafe_output_stream;
-    for (int page_num = 0; page_num < article_proto->pages_size(); ++page_num) {
-      unsafe_output_stream << article_proto->pages(page_num).html();
-    }
-    unsafe_article_html = unsafe_output_stream.str();
-    text_direction = article_proto->pages(0).text_direction();
+  if (article_proto->pages_size() == 0 || !article_proto->pages(0).has_html()) {
+    return "";
   }
 
-  EnsureNonEmptyTitleAndContent(&title, &unsafe_article_html);
-
-  std::string original_url;
-  if (article_proto->pages_size() > 0 && article_proto->pages(0).has_url()) {
-    original_url = article_proto->pages(0).url();
+  std::ostringstream unsafe_output_stream;
+  for (int page_num = 0; page_num < article_proto->pages_size(); ++page_num) {
+    unsafe_output_stream << article_proto->pages(page_num).html();
   }
 
-  return ReplaceHtmlTemplateValues(
-      title, text_direction, unsafe_article_html, "hidden", original_url,
-      theme, font_family);
+  std::string output;
+  base::StringValue value(unsafe_output_stream.str());
+  base::JSONWriter::Write(&value, &output);
+  EnsureNonEmptyContent(&output);
+  std::string page_update("addToPage(");
+  page_update += output + ");";
+  return page_update + GetToggleLoadingIndicatorJs(true);
 }
 
 const std::string GetErrorPageHtml(
@@ -202,10 +205,8 @@ const std::string GetErrorPageHtml(
     const DistilledPagePrefs::FontFamily font_family) {
   std::string title = l10n_util::GetStringUTF8(
       IDS_DOM_DISTILLER_VIEWER_FAILED_TO_FIND_ARTICLE_TITLE);
-  std::string content = l10n_util::GetStringUTF8(
-      IDS_DOM_DISTILLER_VIEWER_FAILED_TO_FIND_ARTICLE_CONTENT);
-  return ReplaceHtmlTemplateValues(
-      title, "", content, "hidden", "", theme, font_family);
+  return ReplaceHtmlTemplateValues(title, "auto", "hidden", "", theme,
+                                   font_family);
 }
 
 const std::string GetCss() {