Bug 221521 [Markers] New markers API needs to be pared down
We have too much API in some of the new classes and they can be moved to internals
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerSupportInternalUtilities.java
* Returns the highest severity of the given marker item and all its
	 * children.
	 * 
	 * @param markerItem
	 * @return the severity
	 */
	public static int getHighestSeverity(MarkerItem markerItem) {
		if (markerItem instanceof MarkerCategory) {
			MarkerCategory category = (MarkerCategory) markerItem;
			return category.getHighestSeverity();
		}
		IMarker marker = markerItem.getMarker();
		Assert.isNotNull(marker);
		return marker.getAttribute(IMarker.SEVERITY, IMarker.SEVERITY_INFO);
	}
	/**
	 * Return the children of the given marker item (may return an array of
	 * length 0)
	 * 
	 * @param markerItem
	 * @return the children
	 */
	public static MarkerItem[] getChildren(MarkerItem markerItem) {
		if (markerItem instanceof MarkerCategory) {
			return ((MarkerCategory) markerItem).getChildren();
		}
		return EMPTY_MARKER_ITEM_ARRAY;
	}
}