1874203 - Expose a chrome-only way to tell the size of the clipboard

Status: NEW

(Core :: DOM: Copy & Paste and Drag & Drop, task)

Description

[Marco Bonardo [:mak]]

In cases like Bug 1866710 we'd like to periodically poll the text in the clipboard and enable some UI if what we find matches our expectations.
Unfortunately that (https://searchfox.org/mozilla-central/rev/961a9e56a0b5fa96ceef22c61c5e75fb6ba53395/browser/base/content/browser.js#3060) may be particularly slow if the clipboard contains a very large chunk of text, like 100MB.
It would be nice to have an API to either:

• get the size, or an estimate of what's in the clipboard
• getDataIfSmallerThan(transfer, clipboard, maxsize)

Thoughts or suggestions on how we could workaround the problem otherwise are welcome.