Bug 267117 [JFace] Provide possibility for subclasses to check if a column is visible in ViewerRow
Currently this is decided by checking with width but this makes Nebula-Grid fail.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ViewerRow.java
/**
 * ViewerRow is the abstract superclass of the part that represents items in a
 * Table or Tree. Implementors of {@link ColumnViewer} have to provide a
 * concrete implementation for the underlying widget
 * 
 * @since 3.3
 * 
 */
public abstract class ViewerRow implements Cloneable {
	/**
	 * Constant denoting the row above the current one (value is 1).
	 * 
	 * @see #getNeighbor(int, boolean)
	 */
	public static final int ABOVE = 1;
	/**
	 * Constant denoting the row below the current one (value is 2).
	 * 
	 * @see #getNeighbor(int, boolean)
	 */
	public static final int BELOW = 2;
	private static final String KEY_TEXT_LAYOUT = Policy.JFACE
			+ "styled_label_key_"; 
	/**
	 * Get the bounds of the entry at the columnIndex,
	 * 
	 * @param columnIndex
	 * @return {@link Rectangle}
	 */
	public abstract Rectangle getBounds(int columnIndex);