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
.historyNotification(event);
			} catch (Exception e) {
				handleNotificationException(e);
			}
	}
	
	/*
	 * Notify listeners that an operation is about to undo.
	 */
	protected void notifyAboutToUndo(IUndoableOperation operation) {
		if (DEBUG_OPERATION_HISTORY_NOTIFICATION) {
			System.out.print("OPERATIONHISTORY >>> ABOUT_TO_UNDO ");  
			System.out.print(operation);
			System.out.println();
		}
		OperationHistoryEvent event = new OperationHistoryEvent(
				OperationHistoryEvent.ABOUT_TO_UNDO, this, operation);
		preNotifyOperation(operation, event);
		for (int i = 0; i < listeners.size(); i++)
			try {
				((IOperationHistoryListener) listeners.get(i))
					.historyNotification(event);
			} catch (Exception e) {
				handleNotificationException(e);
			}
	}
	/*
	 * Notify listeners that an operation has been added.
	 */
	protected void notifyAdd(IUndoableOperation operation) {