Expose internal treegrid role, do some cleanup for table/grid/treegrid handling

content/browser/accessibility/browser_accessibility_win.cc

Index: content/browser/accessibility/browser_accessibility_win.cc
diff --git a/content/browser/accessibility/browser_accessibility_win.cc b/content/browser/accessibility/browser_accessibility_win.cc
index 045aad7b42b156a85f6ca357bebe28f41ac75fda..acaf7b4a960175708a1b04fcab4687de11a43e98 100644
--- a/content/browser/accessibility/browser_accessibility_win.cc
+++ b/content/browser/accessibility/browser_accessibility_win.cc
@@ -3802,7 +3802,7 @@ void BrowserAccessibilityWin::UpdateStep1ComputeWinAttributes() {
   // Expose table cell index.
   if (IsCellOrTableHeaderRole()) {
     BrowserAccessibility* table = PlatformGetParent();
-    while (table && table->GetRole() != ui::AX_ROLE_TABLE)
+    while (table && !table->IsTableOrGridOrTreeGridRole())
       table = table->PlatformGetParent();
     if (table) {
       const std::vector<int32_t>& unique_cell_ids =
@@ -5537,16 +5537,9 @@ void BrowserAccessibilityWin::InitRoleAndState() {
     case ui::AX_ROLE_TAB:
       ia_role = ROLE_SYSTEM_PAGETAB;
       break;
-    case ui::AX_ROLE_TABLE: {
-      base::string16 aria_role = GetString16Attribute(
-          ui::AX_ATTR_ROLE);
-      if (aria_role == L"treegrid") {
-        ia_role = ROLE_SYSTEM_OUTLINE;
-      } else {
-        ia_role = ROLE_SYSTEM_TABLE;
-      }
+    case ui::AX_ROLE_TABLE:
+      ia_role = ROLE_SYSTEM_TABLE;
       break;
-    }
     case ui::AX_ROLE_TABLE_HEADER_CONTAINER:
       ia_role = ROLE_SYSTEM_GROUPING;
       ia2_role = IA2_ROLE_SECTION;
@@ -5668,10 +5661,7 @@ bool BrowserAccessibilityWin::IsInTreeGrid(const BrowserAccessibility* item) {
     return false;
   }
 
-  const ui::AXRole role = container->GetRole();
-  return role == ui::AX_ROLE_TREE_GRID ||
-         (role == ui::AX_ROLE_TABLE &&
-          container->GetString16Attribute(ui::AX_ATTR_ROLE) == L"treegrid");
+  return container->GetRole() == ui::AX_ROLE_TREE_GRID;
 }
 
 BrowserAccessibilityWin* ToBrowserAccessibilityWin(BrowserAccessibility* obj) {