In a post on XDA by Mishaal Rahman, he has discovered a few new commits in the open source Chromium gerrit that suggests that this double tapping feature could be coming to Chrome on Android in the future, where it means adding the double tap recognition to media control overlay.
This means that video played in the Chrome browser on Android could soon let users double tap to fast forward or rewind videos, which should make shipping through videos a lot more convenient than trying to scrub the video using your finger. Rahman notes that this feature can actually be enabled on the latest builds of Chrome for Android which requires that users use the Chrome Canary build (v65.0.3301.0) or a comparable Chromium build.
For users who are interested (proceed at your own risk), just type “chrome://flags#enable-modern-media-controls” inside your browser’s address bar minus the quotes and it should be enabled. We expect that Google will eventually roll this feature out to users on a wider scale at a later date, but as of now we have no idea when that will be.