function traverseFileTreePromise(item) {
			return new Promise(function (resolve, reject) {
				if (item.isFile) {
					item.file(function (oFile) {
						aFiles.push(oFile);
						resolve(oFile);
					}, function(err){
						reject(err);
					});
				} else if (item.isDirectory) {
					var dirReader = item.createReader();
					dirReader.readEntries(function (entries) {
						var aEntriesPromises = [];
						for (var i = 0; i < entries.length; i++) {
							aEntriesPromises.push(traverseFileTreePromise(entries[i]));
						}
						resolve(Promise.all(aEntriesPromises));
					});
				}
			});
		}
Provides access to the instance of the inner {@link sap.m.List} control, so that it can be customized.
@return {sap.m.List} The inner {@link sap.m.List} control.
@public