Bug 26109 [Dialogs] Need a FormData version of the button sizing API
The button sizing API in Dialog assumes the developer wants a GridData. We should promote the FormData version in PathVariablesDialog to Dialog.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/Dialog.java
*/
	private HashMap buttons = new HashMap();
	
	/**
	 * Font metrics to use for determining pixel sizes.
	 */
	private FontMetrics fontMetrics;
	
	/**
	 * Number of horizontal dialog units per character, value <code>4</code>. 
	 */
	private static final int HORIZONTAL_DIALOG_UNIT_PER_CHAR = 4;
	
	/**
	 * Number of vertical dialog units per character, value <code>8</code>. 
	 */
	private static final int VERTICAL_DIALOG_UNITS_PER_CHAR = 8;
	
/**
 * Returns the number of pixels corresponding to the
 * height of the given number of characters.
 * <p>
 * The required <code>FontMetrics</code> parameter may be created in the 
 * following way:
 * <code>
 * 	GC gc = new GC(control);
 *	gc.setFont(control.getFont());
 *	fontMetrics = gc.getFontMetrics();
 *	gc.dispose();
 * </code>