Merge to M59: Only skip certain hidden elements at MHTML serialization

chrome/browser/download/save_page_browsertest.cc

 // Copyright (c) 2012 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 <stddef.h>
 #include <stdint.h>
 #include <string>
 #include <utility>
 #include <vector>
 
@@ skipping 1286 matching lines @@
   content::SavePageType save_page_type = GetParam();
 
   std::string arr[] = {
       "style.htm: af84c3ca-0fc6-4b0d-bf7a-5ac18a4dab62",
       "frameF: c9539ccd-47b0-47cf-a03b-734614865872",
   };
   std::vector<std::string> expected_substrings(std::begin(arr), std::end(arr));
 
   GURL url(embedded_test_server()->GetURL("a.com", "/save_page/style.htm"));
 
-  // The original page has 7 iframes. 2 of them are both hidden and affecting
-  // no layout. So these two are excluded from the saved page.
-  TestOriginalVsSavedPage(save_page_type, url, 7, 5, expected_substrings);
+  // The original page has 7 iframes. One of them that contains hidden attribute
+  // will be excluded from the saved page.
+  TestOriginalVsSavedPage(save_page_type, url, 7, 6, expected_substrings);
 }
 
 // Test for saving a page with broken subresources:
 // - Broken, undecodable image (see also https://crbug.com/586680)
 // - Broken link, to unresolvable host (see also https://crbug.com/594219)
 IN_PROC_BROWSER_TEST_P(SavePageOriginalVsSavedComparisonTest, BrokenImage) {
   // Clear resolver rules to make sure that *.no.such.host used in the test html
   // doesn't resolve to 127.0.0.1
   host_resolver()->ClearRules();
 
@@ skipping 10 matching lines @@
   TestOriginalVsSavedPage(save_page_type, url, 1, 1, expected_substrings);
 }
 
 INSTANTIATE_TEST_CASE_P(
     SaveType,
     SavePageOriginalVsSavedComparisonTest,
     ::testing::Values(content::SAVE_PAGE_TYPE_AS_COMPLETE_HTML,
                       content::SAVE_PAGE_TYPE_AS_MHTML));
 
 }  // namespace