add test for visibility detection

components/dom_distiller/content/distiller_page_web_contents_browsertest.cc

 // Copyright 2013 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 "base/memory/weak_ptr.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
 #include "base/values.h"
 #include "components/dom_distiller/content/distiller_page_web_contents.h"
 #include "components/dom_distiller/core/distiller_page.h"
@@ skipping 100 matching lines @@
   DistillPage(run_loop.QuitClosure(), "/simple_article.html");
   run_loop.Run();
 
   // A relative link should've been updated.
   EXPECT_THAT(page_info_.get()->html,
               ContainsRegex("src=\"http://127.0.0.1:.*/relativeimage.png\""));
   EXPECT_THAT(page_info_.get()->html,
               HasSubstr("src=\"http://www.google.com/absoluteimage.png\""));
 }
 
+IN_PROC_BROWSER_TEST_F(DistillerPageWebContentsTest, VisibilityDetection) {
+  DistillerPageWebContents distiller_page(
+      shell()->web_contents()->GetBrowserContext());
+  distiller_page_ = &distiller_page;
+
+  // visble_style.html and invisible_style.html only differ by the visibility
+  // internal stylesheet.
+
+  {
+    base::RunLoop run_loop;
+    DistillPage(run_loop.QuitClosure(), "/visible_style.html");
+    run_loop.Run();
+    EXPECT_THAT(page_info_.get()->html, HasSubstr("Lorem ipsum"));
+  }
+
+  {
+    base::RunLoop run_loop;
+    DistillPage(run_loop.QuitClosure(), "/invisible_style.html");
+    run_loop.Run();
+    EXPECT_THAT(page_info_.get()->html, Not(HasSubstr("Lorem ipsum")));
+  }
+}
+
 }  // namespace dom_distiller