Added ability to distinguished between rich and plain text editables on accessibility objects.

Source/modules/accessibility/AXLayoutObject.h

 /*
  * Copyright (C) 2008 Apple 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 67 matching lines @@
     // Overridden from AXObject.
     //
 
     virtual void init() override;
     virtual void detach() override;
     virtual bool isDetached() const override { return !m_layoutObject; }
     virtual bool isAXLayoutObject() const override { return true; }
 
     // Check object role or purpose.
     virtual bool isAttachment() const override;
+    virtual bool isContentRichlyEditable() const override;

[dmazzoni, 2015/06/04 03:45:26]

As I said in the other change, maybe just isRichlyEditable, but I don't have
strong feelings

     virtual bool isLinked() const override;
     virtual bool isLoaded() const override;
     virtual bool isOffScreen() const override;
     virtual bool isReadOnly() const override;
     virtual bool isVisited() const override;
 
     // Check object state.
     virtual bool isFocused() const override;
     virtual bool isSelected() const override;
 
@@ skipping 129 matching lines @@
     VisibleSelection selection() const;
     int indexForVisiblePosition(const VisiblePosition&) const;
     void accessibilityChildrenFromAttribute(QualifiedName attr, AccessibilityChildrenVector&) const;
 };
 
 DEFINE_AX_OBJECT_TYPE_CASTS(AXLayoutObject, isAXLayoutObject());
 
 } // namespace blink
 
 #endif // AXLayoutObject_h