Bug 88838 [Undo] - API cleanup - remove IContextConsultingOperationApprover
Early on this was involved in scenarios where editors examined other operations. This is no longer used. Operation approvers generally apply to all contexts and are installed at the OperationHistory level. Until there is a concrete need for this API it should be removed. It is gratuitous at this point.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/operations/DefaultOperationHistory.java
*/
    public static boolean DEBUG_OPERATION_HISTORY_APPROVAL = false;
	
	protected static final int DEFAULT_LIMIT = 20;
	
	/**
	 * An operation info status describing the condition that there is no available
	 * operation for redo.
	 */
	public static final IStatus NOTHING_TO_REDO_STATUS = new OperationStatus(
			IStatus.INFO, OperationStatus.NOTHING_TO_REDO,
			"No operation to redo"); 
	/**
	 * An operation info status describing the condition that there is no available
	 * operation for undo.
	 */
	public static final IStatus NOTHING_TO_UNDO_STATUS = new OperationStatus(
			IStatus.INFO, OperationStatus.NOTHING_TO_UNDO,
			"No operation to undo"); 
	/**
	 * An operation error status describing the condition that the operation available
	 * for execution, undo or redo is not in a valid state for the action to be
	 * performed.
	 */
	public static final IStatus OPERATION_INVALID_STATUS = new OperationStatus(
			IStatus.ERROR, OperationStatus.OPERATION_INVALID,
			"Operation is not valid"); 
	/**
	 * the list of {@link IOperationApprover}s
	 */