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

third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

 /*
  * Copyright (C) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 1468 matching lines @@
     case kSliderRole:
     case kSplitterRole:
     case kTabListRole:
     case kToolbarRole:
       if (orientation == kAccessibilityOrientationUndefined)
         orientation = kAccessibilityOrientationHorizontal;
 
       return orientation;
     case kRadioGroupRole:
     case kTreeGridRole:
-    // TODO(nektar): Fix bug 532670 and remove table role.
-    case kTableRole:
       return orientation;
     default:
       return AXObject::Orientation();
   }
 }
 
 AXObject::AXObjectVector AXNodeObject::RadioButtonsInGroup() const {
   AXObjectVector radio_buttons;
   if (!node_ || RoleValue() != kRadioButtonRole)
     return radio_buttons;
@@ skipping 1718 matching lines @@
     return String();
   return ToTextControlElement(node)->StrippedPlaceholder();
 }
 
 DEFINE_TRACE(AXNodeObject) {
   visitor->Trace(node_);
   AXObject::Trace(visitor);
 }
 
 }  // namespace blink