And they've already started
Just last week, Google took a huge step in eliminating Adobe Flash from the web. Soon HTML5, rather than Flash, will be the default web player when HTML5 is available. Flash will remain part of Chrome for now, but by the end of the year will not be a listed plugin or supported media type.
Google says that when a user browses a site that needs the Flash Player, they will be prompted to allow it on the site. If the user accepts, Chrome will refresh the page, unhide Flash Player and remember their choice for the site. If a site doesn’t notice Chrome’s hidden Flash Player and the user goes to Adobe’s download page, Chrome will instead offer to use its Flash Player.
Google will temporarily exclude the ten websites with the highest Flash usage, including YouTube and Facebook. Take the open-source Chromium web browser, which unlike Chrome does not have Flash pre-installed, for example. Some YouTube videos will not play without Flash (some monetized content requires the legacy player to properly display ads). Even more surprising was that no videos on Facebook will play without Flash, despite their move towards HTML5 last December. Google’s list of sites on which to allow Flash Player could change by the end of the year. (And likely will with enough user complaints.)
"No videos will play on Facebook without Flash."
Some may wonder why this is a big deal. The answer is that Flash is one of today’s most insecure web technologies. Two weeks ago, Adobe patched a zero-day vulnerability and at least twenty-five other bugs.