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
* @param columnIndex
	 *            the index of the column
	 * @return styleRanges the styled ranges
	 * 
	 * @since 3.4
	 */
	public StyleRange[] getStyleRanges(int columnIndex) {
		return (StyleRange[]) getItem().getData(KEY_TEXT_LAYOUT + columnIndex);
	}
	int getWidth(int columnIndex) {
		return getBounds(columnIndex).width;
	}
	/**
	 * Scrolls the cell at this index into view
	 * <p>
	 * <b>Because of backwards API compatibility the default implementation is a
	 * no-op. Implementators of {@link ColumnViewer} should overwrite this
	 * method if their widget supports reordered columns</b>
	 * </p>
	 * 
	 * @param columnIndex
	 *            the column index
	 * @return return <code>true</code> when the cell is scrolled into view
	 * @since 3.5
	 */
	protected boolean scrollCellIntoView(int columnIndex) {
		return false;
	}
}