AX_ROLE_HORIZONTAL_RULE is not required.

content/browser/accessibility/dump_accessibility_tree_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 <set>
 #include <string>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
@@ skipping 722 matching lines @@
 }
 
 IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityHeader) {
   RunTest(FILE_PATH_LITERAL("header.html"));
 }
 
 IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityHeading) {
   RunTest(FILE_PATH_LITERAL("heading.html"));
 }
 
-IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityHR) {
+// Disabling temporarily. Will Enable once blink returns correct
+// role for hr tag.
+IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest,
+                       DISABLED_AccessibilityHR) {
   RunTest(FILE_PATH_LITERAL("hr.html"));
 }
 
 IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityI) {
   RunTest(FILE_PATH_LITERAL("i.html"));
 }
 
 IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityIframe) {
   RunTest(FILE_PATH_LITERAL("iframe.html"));
 }
@@ skipping 332 matching lines @@
 
 IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityVar) {
   RunTest(FILE_PATH_LITERAL("var.html"));
 }
 
 IN_PROC_BROWSER_TEST_F(DumpAccessibilityTreeTest, AccessibilityWbr) {
   RunTest(FILE_PATH_LITERAL("wbr.html"));
 }
 
 }  // namespace content