Clipboard API parity

[rebornix]

Here is a list of clipboard api issues we are currently facing on Web.

• Workaround user permission
  • Write
    • Clipboard requests from extensions running in Web worker in Safari not classified by Safari as "in response to a user gesture" and will reject. We turn every click/keydown to clipboard request and any clipboard write is then classified as response to a user gesture.
    • Otherwise, use navigator.clipboard.writeText
    • Lastly document.execCommand('copy')
  • Read: navigator.clipboard.readText. To avoid prompt for user permission, we don't allow keybinding customizations.
• Electron API parity Add access to electron clipboard.readHTML() API for Extensions #140976, Provide full electron clipboard API parity to extensions #139761
  • readText/writeText
  • readHTML/writeHTML
  • readRTL/writeRTL
  • readImage/writeImage
  • availableFormats
  • readBuffer/writeBuffer
• Firefox Clipboard Service API not supported in FF #84084 (comment)
  • readText: only available in Browser extensions
  • writeText: available without permission in secure contexts and browser extensions, but only from user-initiated event callbacks
  • read/write(data: ClipboardItem[]): available when users have browser preference dom.events.asyncClipboard.dataTransfer set to true
• Copy large text fails Fails To Copy Large Text #123030.