add getDirectory() and other assorted changes related to OPFS

[chrisdavidmills]

Description

Chrome 109 sees the Origin Private File System features of the File System API enabled in Chrome Android and WebView. This PR makes some changes related to those updates. Most notably:

• I've broken out the details of the OPFS into its own section on the main File System Access API landing page. Any mentions of the OPFS on other pages now link to this section rather than the spec.
• I've added a page for StorageManager.getDirectory(), as it was missing before.

See my research document for more details on the changes made: https://docs.google.com/document/d/1rPYCw13kIrTnSvUaStCoDFTyeYHXy7tgykiumnccGTI/edit#

Motivation

Additional details

Related issues and pull requests

[github-actions]

Preview URLs (16 pages)

• /en-US/docs/Web/API/FileSystemDirectoryHandle/entries
• /en-US/docs/Web/API/FileSystemDirectoryHandle/getDirectoryHandle
• /en-US/docs/Web/API/FileSystemDirectoryHandle/getFileHandle
• /en-US/docs/Web/API/FileSystemDirectoryHandle/keys
• /en-US/docs/Web/API/FileSystemDirectoryHandle/removeEntry
• /en-US/docs/Web/API/FileSystemDirectoryHandle/resolve
• /en-US/docs/Web/API/FileSystemDirectoryHandle/values
• /en-US/docs/Web/API/FileSystemDirectoryHandle
• /en-US/docs/Web/API/FileSystemFileHandle/createSyncAccessHandle
• /en-US/docs/Web/API/FileSystemHandle/isSameEntry
• /en-US/docs/Web/API/FileSystemHandle/kind
• /en-US/docs/Web/API/FileSystemHandle/name
• /en-US/docs/Web/API/FileSystemSyncAccessHandle
• /en-US/docs/Web/API/File_System_Access_API
• /en-US/docs/Web/API/StorageManager/getDirectory
• /en-US/docs/Web/API/StorageManager

External URLs (4)

URL: /en-US/docs/Web/API/StorageManager/getDirectory
Title: StorageManager.getDirectory()

• FileSystemSyncAccessHandle contains async methods whatwg/fs#7 (1 time) (Note! This may be a new URL 👀)

---

URL: /en-US/docs/Web/API/File_System_Access_API
Title: File System Access API

• https://developer.chrome.com/en/articles/file-handling/ (1 time) (Note! This may be a new URL 👀)
• https://fs.spec.whatwg.org/ (1 time) (Note! This may be a new URL 👀)
• Specify error mappings whatwg/fs#57 (1 time) (Note! This may be a new URL 👀)

(comment last updated: 2022-12-07 08:24:04)

[a-sully]

Mostly LGTM!

[a-sully]

I don't have permission to actually approve this change, but LGTM! 👍

[chrisdavidmills]

@a-sully no worries; thanks a lot for the tech review!