Add grid/flex layout support for <fieldset>

content/browser/accessibility/accessibility_win_browsertest.cc

Index: content/browser/accessibility/accessibility_win_browsertest.cc
diff --git a/content/browser/accessibility/accessibility_win_browsertest.cc b/content/browser/accessibility/accessibility_win_browsertest.cc
index 546286e42ee071a62a2ee8cd4ff250f02452150d..5971f1f434559e74ed01601b8feeedaffe889887 100644
--- a/content/browser/accessibility/accessibility_win_browsertest.cc
+++ b/content/browser/accessibility/accessibility_win_browsertest.cc
@@ -974,7 +974,7 @@ IN_PROC_BROWSER_TEST_F(AccessibilityWinBrowserTest, TestRoleGroup) {
       "<fieldset></fieldset><div role=group></div>");
 
   // Check the browser's copy of the renderer accessibility tree.
-  AccessibleChecker grouping1_checker(std::wstring(), ROLE_SYSTEM_GROUPING,
+  AccessibleChecker grouping1_checker(std::wstring(), ROLE_SYSTEM_CLIENT,

[aboxhall, 2016/07/27 17:21:50]

I'm guessing this is a result of the "anonymous inner block" being added.
Ideally, the results of these tests shouldn't change at all, just like the pixel
tests haven't changed - this is going to affect the user experience for
assistive technology users. We may need to explore if some extra work needs to
be done in modules/accessibility in Blink.

                                       std::wstring());
   AccessibleChecker grouping2_checker(std::wstring(), ROLE_SYSTEM_GROUPING,
                                       std::wstring());