b321d441_avaScript_APIs___Google_Chrome__Description
[Name] fileSystem [Since] 23 [Description] 
Use the chrome.fileSystem API to create, read, navigate, and write to the user's local file system. With this API, Chrome Apps can read and write to a user-selected location. For example, a text editor app can use the API to read and write local documents. All failures are notified via chrome.runtime.lastError.
JavaScript APIs - Google Chrome
Description