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

content/browser/accessibility/browser_accessibility_cocoa.mm

 // 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.
 
 #import "content/browser/accessibility/browser_accessibility_cocoa.h"
 
 #include <execinfo.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
@@ skipping 760 matching lines @@
     children_.reset();
   } else {
     [ToBrowserAccessibilityCocoa(browserAccessibility_->PlatformGetParent())
         childrenChanged];
   }
 }
 
 - (NSArray*)columnHeaders {
   if (![self instanceActive])
     return nil;
-  if ([self internalRole] != ui::AX_ROLE_TABLE &&
-      [self internalRole] != ui::AX_ROLE_GRID) {
+  if (!browserAccessibility_->IsTableOrGridOrTreeGridRole()) {
     return nil;
   }
 
   NSMutableArray* ret = [[[NSMutableArray alloc] init] autorelease];
   const std::vector<int32_t>& uniqueCellIds =
       browserAccessibility_->GetIntListAttribute(ui::AX_ATTR_UNIQUE_CELL_IDS);
   for (size_t i = 0; i < uniqueCellIds.size(); ++i) {
     int id = uniqueCellIds[i];
     BrowserAccessibility* cell =
         browserAccessibility_->manager()->GetFromID(id);
@@ skipping 207 matching lines @@
       grabbed == "true")
     return [NSNumber numberWithBool:YES];
 
   return [NSNumber numberWithBool:NO];
 }
 
 - (id)header {
   if (![self instanceActive])
     return nil;
   int headerElementId = -1;
-  if ([self internalRole] == ui::AX_ROLE_TABLE ||
-      [self internalRole] == ui::AX_ROLE_GRID) {
+  if (browserAccessibility_->IsTableOrGridOrTreeGridRole()) {
     browserAccessibility_->GetIntAttribute(
         ui::AX_ATTR_TABLE_HEADER_ID, &headerElementId);
   } else if ([self internalRole] == ui::AX_ROLE_COLUMN) {
     browserAccessibility_->GetIntAttribute(
         ui::AX_ATTR_TABLE_COLUMN_HEADER_ID, &headerElementId);
   } else if ([self internalRole] == ui::AX_ROLE_ROW) {
     browserAccessibility_->GetIntAttribute(
         ui::AX_ATTR_TABLE_ROW_HEADER_ID, &headerElementId);
   }
 
@@ skipping 487 matching lines @@
   default:
     break;
   }
 
   return NSAccessibilityRoleDescription(role, nil);
 }
 
 - (NSArray*)rowHeaders {
   if (![self instanceActive])
     return nil;
-  if ([self internalRole] != ui::AX_ROLE_TABLE &&
-      [self internalRole] != ui::AX_ROLE_GRID) {
+  if (!browserAccessibility_->IsTableOrGridOrTreeGridRole()) {
     return nil;
   }
 
   NSMutableArray* ret = [[[NSMutableArray alloc] init] autorelease];
   const std::vector<int32_t>& uniqueCellIds =
       browserAccessibility_->GetIntListAttribute(ui::AX_ATTR_UNIQUE_CELL_IDS);
   for (size_t i = 0; i < uniqueCellIds.size(); ++i) {
     int id = uniqueCellIds[i];
     BrowserAccessibility* cell =
         browserAccessibility_->manager()->GetFromID(id);
@@ skipping 1368 matching lines @@
 }
 
 - (BOOL)accessibilityNotifiesWhenDestroyed {
   // Indicate that BrowserAccessibilityCocoa will post a notification when it's
   // destroyed (see -detach). This allows VoiceOver to do some internal things
   // more efficiently.
   return YES;
 }
 
 @end