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/IOperationHistory.java
*            info for prompting the user. If an IAdaptable is provided,
	 *            callers are encourated to provide an adapter for the
	 *            org.eclipse.swt.widgets.Shell.class.
	 * 
	 * @return the IStatus indicating whether the undo succeeded.
	 * 
	 * The severity code in the returned status describes whether the operation
	 * succeeded and whether it remains in the history. <code>OK</code>
	 * severity indicates that the undo operation was successful and that the
	 * operation has been placed on the redo history. Listeners will receive the
	 * <code>UNDONE</code> notification.
	 * 
	 * <code>CANCEL</code> severity indicates that the user cancelled the
	 * operation and that the operation remains in the undo history.
	 * <code>ERROR</code> severity indicates that the operation could not
	 * successfully be undone. The operation will remain at its current location
	 * in the history, and callers must explicitly remove it if desired. Any
	 * other severity code is not interpreted by the history, and is simply
	 * passed back to the caller. For all severities other than <code>OK</code>,
	 * listeners will receive the <code>OPERATION_NOT_OK</code> notification
	 * instead of the <code>UNDONE</code> notification.
	 * 
	 * @throws ExecutionException
	 *             if an exception occurred during undo.
	 */
	IStatus undoOperation(IUndoableOperation operation,
			IProgressMonitor monitor, IAdaptable info)
			throws ExecutionException;
}