Bug 63159 [Progress] Progress dialog "Run in Background" button does not resize with larger font
If you set the dialog font to something large, the "Run in background" button does not correctly resize.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/Dialog.java
* Returns the number of pixels corresponding to the width 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>
	 * </p>
	 * 
	 * @param fontMetrics
	 *            used in performing the conversion
	 * @param chars
	 *            the number of characters
	 * @return the number of pixels
	 * @since 2.0
	 */
	public static int convertWidthInCharsToPixels(FontMetrics fontMetrics,
			int chars) {
		return fontMetrics.getAverageCharWidth() * chars;
	}
	/**
	 * Shortens the given text <code>textValue</code> so that its width in
	 * pixels does not exceed the width of the given control. Overrides
	 * characters in the center of the original string with an ellipsis ("...")
	 * if necessary. If a <code>null</code> value is given, <code>null</code>
	 * is returned.
	 *