In a Google Groups thread named "Intent to implement: HTML5 by Default," the Google developers have shared their cunning plans for the new feature to appear in Chromium builds in Q4 2016.

Anthony LaForge, Technical Program Manager at Google said that if a site offers HTML5 this change will make that the primary experience.

"We will continue to ship Flash Player with Chrome, and if a site truly requires Flash, a prompt will appear at the top of the page when the user first visits that site, giving them the option of allowing it to run for that site."

The Chromium team will basically implement a permanent "Ask to activate" feature for all websites running Flash content, similar to what Firefox has been optionally providing its users for some time now.

LaForge said that this was possible because HTML5 was mature and could deliver an excellent user experience.
"While Flash historically has been critical for rich media on the web, today in many cases HTML5 provides a more integrated media experience with faster load times and lower power consumption. A whitelist will allow default Flash playback for ten major sites"

To avoid "overprompting" a whitelist will allow ten major websites to continue to show Flash content by default without pestering users with "Allow domain.com to run Flash Player" prompts. The whitelist will be in effect one year only.

The list includes the domains of YouTube, Facebook, Yahoo, VK, Live, Yandex, OK.ru, Twitch, Amazon, and Mail.ru, the biggest sites running Flash content today.

Adobe still has not announced that it is killing off Flash or will stop updating it, but it does look like it is on its way out.