display error message for empty distilled content

also:
- ensure that error message is displayed for empty title
- move dom_distiller_viewer.html/js from content to core dir
- added tests.

BUG=403066

Review URL: https://codereview.chromium.org/563923002

Cr-Commit-Position: refs/heads/master@{#296719}

components/components_tests.gyp

@@ -860,8 +860,6 @@
           'defines!': ['CONTENT_IMPLEMENTATION'],
           'dependencies': [
             'components.gyp:autofill_content_browser',
-            'components.gyp:dom_distiller_content',
-            'components.gyp:dom_distiller_core',
             'components.gyp:password_manager_content_renderer',
             'components.gyp:pref_registry_test_support',
             'components_resources.gyp:components_resources',
@@ -876,6 +874,11 @@
             '../skia/skia.gyp:skia',
             '../testing/gmock.gyp:gmock',
             '../testing/gtest.gyp:gtest',
+
+            # Dependencies of dom_distiller
+            'components.gyp:dom_distiller_content',
+            'components.gyp:dom_distiller_core',
+            'components_strings.gyp:components_strings',
           ],
           'include_dirs': [
             '..',

components/dom_distiller/content/distiller_page_web_contents_browsertest.cc

@@ -9,15 +9,20 @@
 #include "components/dom_distiller/content/distiller_page_web_contents.h"
 #include "components/dom_distiller/content/web_contents_main_frame_observer.h"
 #include "components/dom_distiller/core/distiller_page.h"
+#include "components/dom_distiller/core/proto/distilled_article.pb.h"
+#include "components/dom_distiller/core/proto/distilled_page.pb.h"
+#include "components/dom_distiller/core/viewer.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/test/content_browser_test.h"
 #include "content/shell/browser/shell.h"
+#include "grit/components_strings.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "third_party/dom_distiller_js/dom_distiller.pb.h"
+#include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 
 using content::ContentBrowserTest;
@@ -407,4 +412,110 @@ IN_PROC_BROWSER_TEST_F(DistillerPageWebContentsTest, MarkupInfo) {
   EXPECT_EQ(600, markup_image2.height());
 }
 
+IN_PROC_BROWSER_TEST_F(DistillerPageWebContentsTest,
+                       TestTitleAndContentAreNeverEmpty) {
+  const std::string some_title = "some title";
+  const std::string some_content = "some content";
+  const std::string no_title =
+      l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_TITLE);
+  const std::string no_content =
+      l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_CONTENT);
+
+  {  // Test non-empty title and content for article.
+    scoped_ptr<DistilledArticleProto> article_proto(
+        new DistilledArticleProto());
+    article_proto->set_title(some_title);
+    (*(article_proto->add_pages())).set_html(some_content);
+    std::string html = viewer::GetUnsafeArticleHtml(article_proto.get(),
+        DistilledPagePrefs::LIGHT, DistilledPagePrefs::SERIF);
+    EXPECT_THAT(html, HasSubstr(some_title));
+    EXPECT_THAT(html, HasSubstr(some_content));
+    EXPECT_THAT(html, Not(HasSubstr(no_title)));
+    EXPECT_THAT(html, Not(HasSubstr(no_content)));
+  }
+
+  {  // Test empty title and content for article.
+    scoped_ptr<DistilledArticleProto> article_proto(
+        new DistilledArticleProto());
+    article_proto->set_title("");
+    (*(article_proto->add_pages())).set_html("");
+    std::string html = viewer::GetUnsafeArticleHtml(article_proto.get(),
+        DistilledPagePrefs::LIGHT, DistilledPagePrefs::SERIF);
+    EXPECT_THAT(html, HasSubstr(no_title));
+    EXPECT_THAT(html, HasSubstr(no_content));
+    EXPECT_THAT(html, Not(HasSubstr(some_title)));
+    EXPECT_THAT(html, Not(HasSubstr(some_content)));
+  }
+
+  {  // Test missing title and non-empty content for article.
+    scoped_ptr<DistilledArticleProto> article_proto(
+        new DistilledArticleProto());
+    (*(article_proto->add_pages())).set_html(some_content);
+    std::string html = viewer::GetUnsafeArticleHtml(article_proto.get(),
+        DistilledPagePrefs::LIGHT, DistilledPagePrefs::SERIF);
+    EXPECT_THAT(html, HasSubstr(no_title));
+    EXPECT_THAT(html, HasSubstr(no_content));
+    EXPECT_THAT(html, Not(HasSubstr(some_title)));
+    EXPECT_THAT(html, Not(HasSubstr(some_content)));
+  }
+
+  {  // Test non-empty title and missing content for article.
+    scoped_ptr<DistilledArticleProto> article_proto(
+        new DistilledArticleProto());
+    article_proto->set_title(some_title);
+    std::string html = viewer::GetUnsafeArticleHtml(article_proto.get(),
+        DistilledPagePrefs::LIGHT, DistilledPagePrefs::SERIF);
+    EXPECT_THAT(html, HasSubstr(no_title));
+    EXPECT_THAT(html, HasSubstr(no_content));
+    EXPECT_THAT(html, Not(HasSubstr(some_title)));
+    EXPECT_THAT(html, Not(HasSubstr(some_content)));
+  }
+
+  {  // Test non-empty title and content for page.
+    scoped_ptr<DistilledPageProto> page_proto(new DistilledPageProto());
+    page_proto->set_title(some_title);
+    page_proto->set_html(some_content);
+    std::string html = viewer::GetUnsafePartialArticleHtml(page_proto.get(),
+        DistilledPagePrefs::LIGHT, DistilledPagePrefs::SERIF);
+    EXPECT_THAT(html, HasSubstr(some_title));
+    EXPECT_THAT(html, HasSubstr(some_content));
+    EXPECT_THAT(html, Not(HasSubstr(no_title)));
+    EXPECT_THAT(html, Not(HasSubstr(no_content)));
+  }
+
+  {  // Test empty title and content for page.
+    scoped_ptr<DistilledPageProto> page_proto(new DistilledPageProto());
+    page_proto->set_title("");
+    page_proto->set_html("");
+    std::string html = viewer::GetUnsafePartialArticleHtml(page_proto.get(),
+        DistilledPagePrefs::LIGHT, DistilledPagePrefs::SERIF);
+    EXPECT_THAT(html, HasSubstr(no_title));
+    EXPECT_THAT(html, HasSubstr(no_content));
+    EXPECT_THAT(html, Not(HasSubstr(some_title)));
+    EXPECT_THAT(html, Not(HasSubstr(some_content)));
+  }
+
+  {  // Test missing title and non-empty content for page.
+    scoped_ptr<DistilledPageProto> page_proto(new DistilledPageProto());
+    page_proto->set_html(some_content);
+    std::string html = viewer::GetUnsafePartialArticleHtml(page_proto.get(),
+        DistilledPagePrefs::LIGHT, DistilledPagePrefs::SERIF);
+    EXPECT_THAT(html, HasSubstr(no_title));
+    EXPECT_THAT(html, HasSubstr(some_content));
+    EXPECT_THAT(html, Not(HasSubstr(some_title)));
+    EXPECT_THAT(html, Not(HasSubstr(no_content)));
+  }
+
+  {  // Test non-empty title and missing content for page.
+    scoped_ptr<DistilledPageProto> page_proto(new DistilledPageProto());
+    page_proto->set_title(some_title);
+    std::string html = viewer::GetUnsafePartialArticleHtml(page_proto.get(),
+        DistilledPagePrefs::LIGHT, DistilledPagePrefs::SERIF);
+    EXPECT_THAT(html, HasSubstr(some_title));
+    EXPECT_THAT(html, HasSubstr(no_content));
+    EXPECT_THAT(html, Not(HasSubstr(no_title)));
+    EXPECT_THAT(html, Not(HasSubstr(some_content)));
+  }
+}
+
 }  // namespace dom_distiller

components/dom_distiller/core/viewer.cc

@@ -89,6 +89,15 @@ const std::string GetFontCssClass(DistilledPagePrefs::FontFamily font_family) {
   return kSansSerifCssClass;
 }
 
+void EnsureNonEmptyTitleAndContent(std::string* title, std::string* content) {
+  if (title->empty())
+    *title = l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_TITLE);
+  if (content->empty()) {
+    *content = l10n_util::GetStringUTF8(
+        IDS_DOM_DISTILLER_VIEWER_NO_DATA_CONTENT);
+  }
+}
+
 std::string ReplaceHtmlTemplateValues(
     const std::string& title,
     const std::string& content,
@@ -146,6 +155,7 @@ const std::string GetUnsafePartialArticleHtml(
   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);
   std::string original_url = page_proto->url();
   return ReplaceHtmlTemplateValues(
       title, unsafe_article_html, "visible", original_url, theme, font_family);
@@ -166,12 +176,10 @@ const std::string GetUnsafeArticleHtml(
       unsafe_output_stream << article_proto->pages(page_num).html();
     }
     unsafe_article_html = unsafe_output_stream.str();
-  } else {
-    title = l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_TITLE);
-    unsafe_article_html =
-        l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_CONTENT);
   }
 
+  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();

components/resources/dom_distiller_resources.grdp

@@ -3,8 +3,8 @@
   <include name="IDR_ABOUT_DOM_DISTILLER_HTML" file="../dom_distiller/webui/resources/about_dom_distiller.html" flattenhtml="true" allowexternalscript="true" type="BINDATA" />
   <include name="IDR_ABOUT_DOM_DISTILLER_CSS" file="../dom_distiller/webui/resources/about_dom_distiller.css" type="BINDATA" />
   <include name="IDR_ABOUT_DOM_DISTILLER_JS" file="../dom_distiller/webui/resources/about_dom_distiller.js" type="BINDATA" />
-  <include name="IDR_DOM_DISTILLER_VIEWER_HTML" file="../dom_distiller/content/resources/dom_distiller_viewer.html" type="BINDATA" />
-  <include name="IDR_DOM_DISTILLER_VIEWER_JS" file="../dom_distiller/content/resources/dom_distiller_viewer.js" type="BINDATA" />
+  <include name="IDR_DOM_DISTILLER_VIEWER_HTML" file="../dom_distiller/core/html/dom_distiller_viewer.html" type="BINDATA" />
+  <include name="IDR_DOM_DISTILLER_VIEWER_JS" file="../dom_distiller/core/javascript/dom_distiller_viewer.js" type="BINDATA" />
   <include name="IDR_DISTILLER_JS" file="../dom_distiller/core/javascript/domdistiller.js" flattenhtml="true" type="BINDATA" />
   <include name="IDR_DISTILLER_CSS" file="../dom_distiller/core/css/distilledpage.css" type="BINDATA" />
   <include name="IDR_IS_DISTILLABLE_JS" file="../dom_distiller/core/javascript/is_distillable_trigger.js" type="BINDATA" />