chrome/browser/dom_distiller/dom_distiller_viewer_source_browsertest.cc

// 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.

#include <string.h>

#include <memory>
#include <utility>

#include "base/bind.h"
#include "base/command_line.h"
#include "base/guid.h"
#include "base/run_loop.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/utf_string_conversions.h"
#include "chrome/browser/dom_distiller/dom_distiller_service_factory.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/ui/browser.h"
#include "chrome/browser/ui/browser_navigator_params.h"
#include "chrome/browser/ui/tabs/tab_strip_model.h"
#include "chrome/common/chrome_isolated_world_ids.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/test/base/in_process_browser_test.h"
#include "chrome/test/base/ui_test_utils.h"
#include "components/dom_distiller/content/browser/distiller_javascript_utils.h"
#include "components/dom_distiller/content/browser/dom_distiller_viewer_source.h"
#include "components/dom_distiller/core/article_entry.h"
#include "components/dom_distiller/core/distilled_page_prefs.h"
#include "components/dom_distiller/core/distiller.h"
#include "components/dom_distiller/core/dom_distiller_service.h"
#include "components/dom_distiller/core/dom_distiller_switches.h"
#include "components/dom_distiller/core/fake_distiller.h"
#include "components/dom_distiller/core/fake_distiller_page.h"
#include "components/dom_distiller/core/task_tracker.h"
#include "components/dom_distiller/core/url_constants.h"
#include "components/dom_distiller/core/url_utils.h"
#include "components/strings/grit/components_strings.h"
#include "content/public/browser/render_frame_host.h"
#include "content/public/browser/url_data_source.h"
#include "content/public/browser/web_contents.h"
#include "content/public/browser/web_contents_observer.h"
#include "content/public/common/isolated_world_ids.h"
#include "content/public/test/browser_test_utils.h"
#include "testing/gmock/include/gmock/gmock-matchers.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "ui/base/l10n/l10n_util.h"

namespace dom_distiller {

using test::FakeDistiller;
using test::MockDistillerFactory;
using test::MockDistillerPage;
using test::MockDistillerPageFactory;
using testing::HasSubstr;
using testing::Not;

namespace {

const char kGetLoadIndicatorClassName[] =
    "window.domAutomationController.send("
    "document.getElementById('loadingIndicator').className)";

const char kGetContent[] =
    "window.domAutomationController.send("
    "document.getElementById('content').innerHTML)";

const char kGetTitle[] =
    "window.domAutomationController.send("
    "document.title)";

const char kGetBodyClass[] =
    "window.domAutomationController.send("
    "document.body.className)";

const char kGetFontSize[] =
    "window.domAutomationController.send("
    "window.getComputedStyle(document.documentElement).fontSize)";

const unsigned kDarkToolbarThemeColor = 0xFF1A1A1A;

const char kTestDistillerObject[] =
    "window.domAutomationController.send("
    "typeof distiller == 'object')";

void ExpectBodyHasThemeAndFont(content::WebContents* contents,
                               const std::string& expected_theme,
                               const std::string& expected_font) {
  std::string result;
  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetBodyClass, &result));
  EXPECT_THAT(result, HasSubstr(expected_theme));
  EXPECT_THAT(result, HasSubstr(expected_font));
}

}  // namespace

class DomDistillerViewerSourceBrowserTest : public InProcessBrowserTest {
 public:
  DomDistillerViewerSourceBrowserTest() {}
  ~DomDistillerViewerSourceBrowserTest() override {}

  void SetUpOnMainThread() override {
    if (!DistillerJavaScriptWorldIdIsSet()) {
      SetDistillerJavaScriptWorldId(content::ISOLATED_WORLD_ID_CONTENT_END);
    }
  }

  void SetUpCommandLine(base::CommandLine* command_line) override {
    command_line->AppendSwitch(switches::kEnableDomDistiller);
  }

  std::unique_ptr<KeyedService> Build(content::BrowserContext* context) {
    auto distiller_factory = std::make_unique<MockDistillerFactory>();
    distiller_factory_ = distiller_factory.get();
    auto distiller_page_factory = std::make_unique<MockDistillerPageFactory>();
    auto* distiller_page_factory_raw = distiller_page_factory.get();
    auto service = std::make_unique<DomDistillerContextKeyedService>(
        std::move(distiller_factory), std::move(distiller_page_factory),
        std::make_unique<DistilledPagePrefs>(
            Profile::FromBrowserContext(context)->GetPrefs()));
    if (expect_distillation_) {
      // There will only be destillation of an article if the database contains
      // the article.
      FakeDistiller* distiller = new FakeDistiller(true);
      EXPECT_CALL(*distiller_factory_, CreateDistillerImpl())
          .WillOnce(testing::Return(distiller));
    }
    if (expect_distiller_page_) {
      MockDistillerPage* distiller_page = new MockDistillerPage();
      EXPECT_CALL(*distiller_page_factory_raw, CreateDistillerPageImpl())
          .WillOnce(testing::Return(distiller_page));
    }
    return std::move(service);
  }

  void ViewSingleDistilledPage(const GURL& url,
                               const std::string& expected_mime_type);
  void ViewSingleDistilledPageAndExpectErrorPage(const GURL& url);
  void PrefTest(bool is_error_page);

  // Database entries.
  bool expect_distillation_ = false;
  bool expect_distiller_page_ = false;
  MockDistillerFactory* distiller_factory_ = nullptr;
};

// The DomDistillerViewerSource renders untrusted content, so ensure no bindings
// are enabled when the article is not found.
IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       NoWebUIBindingsArticleNotFound) {
  // The article does not exist, so assume no distillation will happen.
  expect_distillation_ = false;
  expect_distiller_page_ = false;
  const GURL url = url_utils::GetDistillerViewUrlFromEntryId(
      kDomDistillerScheme, "DOES_NOT_EXIST");
  ViewSingleDistilledPage(url, "text/html");
}

// The DomDistillerViewerSource renders untrusted content, so ensure no bindings
// are enabled when requesting to view an arbitrary URL.
IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       NoWebUIBindingsViewUrl) {
  // We should expect distillation for any valid URL.
  expect_distillation_ = true;
  expect_distiller_page_ = true;
  GURL original_url("http://www.example.com/1");
  const GURL view_url =
      url_utils::GetDistillerViewUrlFromUrl(kDomDistillerScheme, original_url);
  ViewSingleDistilledPage(view_url, "text/html");
}

void DomDistillerViewerSourceBrowserTest::ViewSingleDistilledPage(
    const GURL& url,
    const std::string& expected_mime_type) {
  // Ensure the correct factory is used for the DomDistillerService.
  dom_distiller::DomDistillerServiceFactory::GetInstance()
      ->SetTestingFactoryAndUse(
          browser()->profile(),
          base::BindRepeating(&DomDistillerViewerSourceBrowserTest::Build,
                              base::Unretained(this)));

  // Navigate to a URL which the source should respond to.
  ui_test_utils::NavigateToURL(browser(), url);

  // Ensure no bindings for the loaded |url|.
  content::WebContents* contents_after_nav =
      browser()->tab_strip_model()->GetActiveWebContents();
  ASSERT_TRUE(contents_after_nav != NULL);
  EXPECT_EQ(url, contents_after_nav->GetLastCommittedURL());
  content::RenderFrameHost* render_frame_host =
      contents_after_nav->GetMainFrame();
  EXPECT_EQ(0, render_frame_host->GetEnabledBindings());
  EXPECT_EQ(expected_mime_type, contents_after_nav->GetContentsMimeType());
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       TestBadUrlErrorPage) {
  GURL url("chrome-distiller://bad");
  ViewSingleDistilledPageAndExpectErrorPage(url);
}

void DomDistillerViewerSourceBrowserTest::
    ViewSingleDistilledPageAndExpectErrorPage(const GURL& url) {
  // Navigate to a distiller URL.
  ViewSingleDistilledPage(url, "text/html");
  content::WebContents* contents =
      browser()->tab_strip_model()->GetActiveWebContents();

  // Wait for the page load to complete as the first page completes the root
  // document.
  content::WaitForLoadStop(contents);

  ASSERT_TRUE(contents != NULL);
  EXPECT_EQ(url, contents->GetLastCommittedURL());

  std::string result;
  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetContent, &result));
  EXPECT_THAT(result,
              HasSubstr(l10n_util::GetStringUTF8(
                  IDS_DOM_DISTILLER_VIEWER_FAILED_TO_FIND_ARTICLE_CONTENT)));
  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetTitle, &result));
  EXPECT_THAT(result,
              HasSubstr(l10n_util::GetStringUTF8(
                  IDS_DOM_DISTILLER_VIEWER_FAILED_TO_FIND_ARTICLE_TITLE)));
}

// The DomDistillerViewerSource renders untrusted content, so ensure no bindings
// are enabled when the CSS resource is loaded. This CSS might be bundle with
// Chrome or provided by an extension.
IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       NoWebUIBindingsDisplayCSS) {
  expect_distillation_ = false;
  expect_distiller_page_ = false;
  // Navigate to a URL which the source should respond to with CSS.
  std::string url_without_scheme = std::string("://foobar/") + kViewerCssPath;
  GURL url(kDomDistillerScheme + url_without_scheme);
  ViewSingleDistilledPage(url, "text/css");
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       EmptyURLShouldNotCrash) {
  // This is a bogus URL, so no distillation will happen.
  expect_distillation_ = false;
  expect_distiller_page_ = false;
  const GURL url(std::string(kDomDistillerScheme) + "://bogus/");
  ViewSingleDistilledPage(url, "text/html");
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       InvalidURLShouldNotCrash) {
  // This is a bogus URL, so no distillation will happen.
  expect_distillation_ = false;
  expect_distiller_page_ = false;
  const GURL url(std::string(kDomDistillerScheme) + "://bogus/foobar");
  ViewSingleDistilledPage(url, "text/html");
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       InvalidURLShouldGetErrorPage) {
  const GURL original_url("http://www.example.com/1");
  const GURL different_url("http://www.example.com/2");
  const GURL view_url =
      url_utils::GetDistillerViewUrlFromUrl(kDomDistillerScheme, original_url);
  // This is a bogus URL, so no distillation will happen.
  const GURL bad_view_url = net::AppendOrReplaceQueryParameter(
      view_url, kUrlKey, different_url.spec());

  ViewSingleDistilledPageAndExpectErrorPage(bad_view_url);
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest, EarlyTemplateLoad) {
  dom_distiller::DomDistillerServiceFactory::GetInstance()
      ->SetTestingFactoryAndUse(
          browser()->profile(),
          base::BindRepeating(&DomDistillerViewerSourceBrowserTest::Build,
                              base::Unretained(this)));

  scoped_refptr<content::MessageLoopRunner> distillation_done_runner =
      new content::MessageLoopRunner;

  FakeDistiller* distiller =
      new FakeDistiller(false, distillation_done_runner->QuitClosure());
  EXPECT_CALL(*distiller_factory_, CreateDistillerImpl())
      .WillOnce(testing::Return(distiller));

  // Navigate to a URL.
  GURL url(dom_distiller::url_utils::GetDistillerViewUrlFromUrl(
      kDomDistillerScheme, GURL("http://urlthatlooksvalid.com")));
  NavigateParams params(browser(), url, ui::PAGE_TRANSITION_TYPED);
  Navigate(&params);
  distillation_done_runner->Run();

  content::WebContents* contents =
      browser()->tab_strip_model()->GetActiveWebContents();

  // Wait for the page load to complete (should only be template).
  content::WaitForLoadStop(contents);
  std::string result;
  // Loading spinner should be on screen at this point.
  EXPECT_TRUE(content::ExecuteScriptAndExtractString(
      contents, kGetLoadIndicatorClassName, &result));
  EXPECT_EQ("visible", result);

  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetContent, &result));
  EXPECT_THAT(result, Not(HasSubstr("content")));

  // Finish distillation and make sure the spinner has been replaced by text.
  std::vector<scoped_refptr<ArticleDistillationUpdate::RefCountedPageProto>>
      update_pages;
  std::unique_ptr<DistilledArticleProto> article(new DistilledArticleProto());

  scoped_refptr<base::RefCountedData<DistilledPageProto>> page_proto =
      new base::RefCountedData<DistilledPageProto>();
  page_proto->data.set_url("http://foo.html");
  page_proto->data.set_html("<div>content</div>");
  update_pages.push_back(page_proto);
  *(article->add_pages()) = page_proto->data;

  ArticleDistillationUpdate update(update_pages, true, false);
  distiller->RunDistillerUpdateCallback(update);

  content::WaitForLoadStop(contents);

  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetContent, &result));
  EXPECT_THAT(result, HasSubstr("content"));
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       DISABLED_DistillerJavaScriptExposed) {
  // Navigate to a distiller URL.
  GURL url(std::string(kDomDistillerScheme) + "://url");
  NavigateParams params(browser(), url, ui::PAGE_TRANSITION_TYPED);
  Navigate(&params);

  content::WebContents* contents =
      browser()->tab_strip_model()->GetActiveWebContents();

  // Wait for the page load to complete (this will be a distiller error page).
  content::WaitForLoadStop(contents);

  // Execute in isolated world; where all distiller scripts are run.
  EXPECT_EQ(true, content::EvalJsWithManualReply(
                      contents, kTestDistillerObject,
                      content::EXECUTE_SCRIPT_DEFAULT_OPTIONS,
                      ISOLATED_WORLD_ID_CHROME_INTERNAL));
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       DistillerJavaScriptNotInMainWorld) {
  // Navigate to a distiller URL.
  GURL url(std::string(kDomDistillerScheme) + "://url");
  NavigateParams params(browser(), url, ui::PAGE_TRANSITION_TYPED);
  Navigate(&params);

  content::WebContents* contents =
      browser()->tab_strip_model()->GetActiveWebContents();

  // Wait for the page load to complete (this will be a distiller error page).
  content::WaitForLoadStop(contents);

  bool result;
  // Execute in main world, the distiller object should not be here.
  EXPECT_TRUE(content::ExecuteScriptAndExtractBool(
      contents, kTestDistillerObject, &result));
  EXPECT_FALSE(result);
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest,
                       DistillerJavaScriptNotExposed) {
  // Navigate to a non-distiller URL.
  GURL url("http://url");
  NavigateParams params(browser(), url, ui::PAGE_TRANSITION_TYPED);
  Navigate(&params);

  content::WebContents* contents =
      browser()->tab_strip_model()->GetActiveWebContents();

  // Wait for the page load to complete.
  content::WaitForLoadStop(contents);

  bool result;
  EXPECT_TRUE(content::ExecuteScriptAndExtractBool(
      contents, kTestDistillerObject, &result));
  EXPECT_FALSE(result);
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest, MultiPageArticle) {
  expect_distillation_ = false;
  expect_distiller_page_ = true;
  dom_distiller::DomDistillerServiceFactory::GetInstance()
      ->SetTestingFactoryAndUse(
          browser()->profile(),
          base::BindRepeating(&DomDistillerViewerSourceBrowserTest::Build,
                              base::Unretained(this)));

  scoped_refptr<content::MessageLoopRunner> distillation_done_runner =
      new content::MessageLoopRunner;

  FakeDistiller* distiller =
      new FakeDistiller(false, distillation_done_runner->QuitClosure());
  EXPECT_CALL(*distiller_factory_, CreateDistillerImpl())
      .WillOnce(testing::Return(distiller));

  // Setup observer to inspect the RenderViewHost after committed navigation.
  content::WebContents* contents =
      browser()->tab_strip_model()->GetActiveWebContents();

  // Navigate to a URL and wait for the distiller to flush contents to the page.
  GURL url(dom_distiller::url_utils::GetDistillerViewUrlFromUrl(
      kDomDistillerScheme, GURL("http://urlthatlooksvalid.com")));
  NavigateParams params(browser(), url, ui::PAGE_TRANSITION_TYPED);
  Navigate(&params);
  distillation_done_runner->Run();

  // Fake a multi-page response from distiller.

  std::vector<scoped_refptr<ArticleDistillationUpdate::RefCountedPageProto>>
      update_pages;
  std::unique_ptr<DistilledArticleProto> article(new DistilledArticleProto());

  // Flush page 1.
  {
    scoped_refptr<base::RefCountedData<DistilledPageProto>> page_proto =
        new base::RefCountedData<DistilledPageProto>();
    page_proto->data.set_url("http://foobar.1.html");
    page_proto->data.set_html("<div>Page 1 content</div>");
    update_pages.push_back(page_proto);
    *(article->add_pages()) = page_proto->data;

    ArticleDistillationUpdate update(update_pages, true, false);
    distiller->RunDistillerUpdateCallback(update);

    // Wait for the page load to complete as the first page completes the root
    // document.
    content::WaitForLoadStop(contents);

    std::string result;
    EXPECT_TRUE(content::ExecuteScriptAndExtractString(
        contents, kGetLoadIndicatorClassName, &result));
    EXPECT_EQ("visible", result);

    EXPECT_TRUE(
        content::ExecuteScriptAndExtractString(contents, kGetContent, &result));
    EXPECT_THAT(result, HasSubstr("Page 1 content"));
    EXPECT_THAT(result, Not(HasSubstr("Page 2 content")));
  }

  // Flush page 2.
  {
    scoped_refptr<base::RefCountedData<DistilledPageProto>> page_proto =
        new base::RefCountedData<DistilledPageProto>();
    page_proto->data.set_url("http://foobar.2.html");
    page_proto->data.set_html("<div>Page 2 content</div>");
    update_pages.push_back(page_proto);
    *(article->add_pages()) = page_proto->data;

    ArticleDistillationUpdate update(update_pages, false, false);
    distiller->RunDistillerUpdateCallback(update);

    std::string result;
    EXPECT_TRUE(content::ExecuteScriptAndExtractString(
        contents, kGetLoadIndicatorClassName, &result));
    EXPECT_EQ("hidden", result);

    EXPECT_TRUE(
        content::ExecuteScriptAndExtractString(contents, kGetContent, &result));
    EXPECT_THAT(result, HasSubstr("Page 1 content"));
    EXPECT_THAT(result, HasSubstr("Page 2 content"));
  }

  // Complete the load.
  distiller->RunDistillerCallback(std::move(article));
  base::RunLoop().RunUntilIdle();

  std::string result;
  EXPECT_TRUE(content::ExecuteScriptAndExtractString(
      contents, kGetLoadIndicatorClassName, &result));
  EXPECT_EQ("hidden", result);
  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetContent, &result));
  EXPECT_THAT(result, HasSubstr("Page 1 content"));
  EXPECT_THAT(result, HasSubstr("Page 2 content"));
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest, PrefChange) {
  PrefTest(false);
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest, PrefChangeError) {
  PrefTest(true);
}

void DomDistillerViewerSourceBrowserTest::PrefTest(bool is_error_page) {
  GURL view_url;
  if (is_error_page) {
    expect_distillation_ = false;
    expect_distiller_page_ = false;
    view_url = GURL("chrome-distiller://bad");
  } else {
    expect_distillation_ = true;
    expect_distiller_page_ = true;
    GURL original_url("http://www.example.com/1");
    view_url = url_utils::GetDistillerViewUrlFromUrl(kDomDistillerScheme,
                                                     original_url);
  }
  content::WebContents* contents =
      browser()->tab_strip_model()->GetActiveWebContents();
  ViewSingleDistilledPage(view_url, "text/html");
  content::WaitForLoadStop(contents);
  ExpectBodyHasThemeAndFont(contents, "light", "sans-serif");

  DistilledPagePrefs* distilled_page_prefs =
      DomDistillerServiceFactory::GetForBrowserContext(browser()->profile())
          ->GetDistilledPagePrefs();

  // Test theme.
  distilled_page_prefs->SetTheme(DistilledPagePrefs::THEME_DARK);
  base::RunLoop().RunUntilIdle();
  ExpectBodyHasThemeAndFont(contents, "dark", "sans-serif");

  // Verify that the theme color for the tab is updated as well.
  EXPECT_EQ(kDarkToolbarThemeColor, contents->GetThemeColor());

  // Test font family.
  distilled_page_prefs->SetFontFamily(
      DistilledPagePrefs::FONT_FAMILY_MONOSPACE);
  base::RunLoop().RunUntilIdle();
  ExpectBodyHasThemeAndFont(contents, "dark", "monospace");

  // Test font scaling.
  std::string result;
  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetFontSize, &result));
  double oldFontSize;
  base::StringToDouble(result, &oldFontSize);

  const double kScale = 1.23;
  distilled_page_prefs->SetFontScaling(kScale);
  base::RunLoop().RunUntilIdle();
  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetFontSize, &result));
  double fontSize;
  base::StringToDouble(result, &fontSize);
  ASSERT_FLOAT_EQ(kScale, fontSize / oldFontSize);
}

IN_PROC_BROWSER_TEST_F(DomDistillerViewerSourceBrowserTest, PrefPersist) {
  expect_distillation_ = false;
  expect_distiller_page_ = false;
  const GURL url("chrome-distiller://bad");
  ui_test_utils::NavigateToURL(browser(), url);
  content::WebContents* contents =
      browser()->tab_strip_model()->GetActiveWebContents();
  content::WaitForLoadStop(contents);

  std::string result;
  DistilledPagePrefs* distilled_page_prefs =
      DomDistillerServiceFactory::GetForBrowserContext(browser()->profile())
          ->GetDistilledPagePrefs();

  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetFontSize, &result));
  double oldFontSize;
  base::StringToDouble(result, &oldFontSize);

  // Set preference.
  const double kScale = 1.23;
  distilled_page_prefs->SetTheme(DistilledPagePrefs::THEME_DARK);
  distilled_page_prefs->SetFontFamily(
      DistilledPagePrefs::FONT_FAMILY_MONOSPACE);
  distilled_page_prefs->SetFontScaling(kScale);

  base::RunLoop().RunUntilIdle();
  ExpectBodyHasThemeAndFont(contents, "dark", "monospace");

  EXPECT_EQ(kDarkToolbarThemeColor, contents->GetThemeColor());
  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetFontSize, &result));
  double fontSize;
  base::StringToDouble(result, &fontSize);
  ASSERT_FLOAT_EQ(kScale, fontSize / oldFontSize);

  // Make sure perf persist across web pages.
  GURL url2("chrome-distiller://bad2");
  ui_test_utils::NavigateToURL(browser(), url2);
  content::WaitForLoadStop(contents);

  base::RunLoop().RunUntilIdle();
  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetBodyClass, &result));
  ExpectBodyHasThemeAndFont(contents, "dark", "monospace");
  EXPECT_EQ(kDarkToolbarThemeColor, contents->GetThemeColor());

  EXPECT_TRUE(
      content::ExecuteScriptAndExtractString(contents, kGetFontSize, &result));
  base::StringToDouble(result, &fontSize);
  ASSERT_FLOAT_EQ(kScale, fontSize / oldFontSize);
}

}  // namespace dom_distiller