function addListToWorkingSet(fileList) {
        DeprecationWarning.deprecationWarning("Use MainViewManager.addListToWorkingSet() instead of DocumentManager.addListToWorkingSet()", true);
        MainViewManager.addListToWorkingSet(MainViewManager.ACTIVE_PANE, fileList);
    }
@deprecated Use MainViewManager.addListToWorkingSet() instead
Adds the given file list to the end of the working set list.
If a file in the list has its own custom viewer, then it
is not added into the working set.
Does not change which document is currently open in the editor.
More efficient than calling addToWorkingSet() (in a loop) for
a list of files because there's only 1 redraw at the end
@param {!Array.<File>} fileList