Why does Google hangouts support sharing desktop without Chrome Extension in latest Chrome?

问题

As far as I know, in browser, such as Chrome, sharing desktop or application needs a Chrome Extension to work, eg:

chrome.permissions.request({
    permissions: ['desktopCapture'],
}

But why does Google Hangouts do not need any extension to capture desktop?

Is there any API of JavaScript for this?

回答1:

As of now, Google Hangouts does use an extension, it's just integrated into Chrome to the point of not being visible.

Source: Chromium issue to remove this special treatment

You can test that it is (stealthily) installed by manually opening

chrome-extension://nkeimhogjdpnpccoofpliimaahmaaome/background.html

At the same time, work is ongoing to support WebRTC spec for screen sharing (getDisplayMedia) in Chrome. It's not yet enabled by default in released Chrome versions, but will be very soon (code is already in the codebase).

Implementation tracking: Chromium issue

来源：https://stackoverflow.com/questions/53410809/why-does-google-hangouts-support-sharing-desktop-without-chrome-extension-in-lat