Four months ago, Google announced to the world that it will be replacing Flash for HTML5. This week, the company has begun its first phase of the great HTML5 rollout.
In a blogpost published by Google, Google has outlined hot HTML5 will be implemented over the coming months. Over the course of the next few months, HTML5 By Default will be enabled for the Chrome browser. The feature is currently enabled for roughly 50% of Chrome 56 beta users while 1% of Chrome 55 Stable users will be given access to this feature within the next few days. Google will be looking to rollout HTML5 By Default to all users in the Chrome 56 Stable build that is coming in February.
By January, Google will be making it so that Flash will only be run when prompted to. These prompts will appear on a site-by-site basis for sites that the use has never visited before. To prevent over-prompting, Google has mentioned that it will tighten the restriction using Site Engagement Index, a heuristic for how much a user interacts with a site based on browsing activity.
Source: Chromium