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
* enforced.  We do not wish to support a global limit in this implementation,
		 * so we throw an exception for a null context.  The rest of the implementation
		 * can handle a null context, so subclasses can override this if a global limit
		 * is desired.
		 */	
		Assert.isNotNull(context);
		limits.put(context, new Integer(limit));
		forceUndoLimit(context, limit);
		forceRedoLimit(context, limit);
	}
	
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.commands.operations.IOperationHistory#undo(org.eclipse.core.commands.operations.IUndoContext, org.eclipse.core.runtime.IProgressMonitor, org.eclipse.core.runtime.IAdaptable)
	 */
	public IStatus undo(IUndoContext context, IProgressMonitor monitor, IAdaptable info) throws ExecutionException{
		Assert.isNotNull(context);
		IUndoableOperation operation = getUndoOperation(context);
		
		if (operation == null)
			return NOTHING_TO_UNDO_STATUS;
		
		if (!operation.canUndo()) {
			if (DEBUG_OPERATION_HISTORY_UNEXPECTED) {
				System.out.print("OPERATIONHISTORY >>> Undo operation not valid - ");  
				System.out.print(operation);
				System.out.println();
			}
			return OPERATION_INVALID_STATUS;