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
* height of the given number of characters.
 * <p>
 * This method may only be called after <code>initializeDialogUnits</code>
 * has been called.
 * </p>
 * <p>
 * Clients may call this framework method, but should not override it.
 * </p>
 *
 * @param chars the number of characters
 * @return the number of pixels
 */
protected int convertHeightInCharsToPixels(int chars) {
	
	if (fontMetrics == null)
		return 0;
	return convertHeightInCharsToPixels(fontMetrics, chars);
}
/**
 * Returns the number of pixels corresponding to the
 * given number of horizontal dialog units.
 * <p>
 * This method may only be called after <code>initializeDialogUnits</code>
 * has been called.
 * </p>
 * <p>
 * Clients may call this framework method, but should not override it.
 * </p>
 *
 * @param dlus the number of horizontal dialog units