The latest release of Chrome Beta doesn't include many big, user-facing changes, but is instead mostly filled with incremental improvements to long-term development goals. The one goodie for end users that you may notice in normal use is the newly-added ability for websites to give you an Android notification with play and pause buttons to control audio.
For websites using up-to-date APIs, audio and video that is over 5 seconds long will result in a notification being displayed for easier control. I think of this somewhat similarly to the desktop version's indicator for noisy tabs.
Here's another look, in GIF form, thanks to Google Developers.
Media playback notifications don't use service workers.
A Googler reached out to clarify that these controls work without the use of service workers, appearing when the browser detects audio or video content that is longer than 5 seconds within <audio> or <video> tags.
This feature utilizes service workers, which were introduced in v40 and help make web apps work better offline and act more like full-fledged applications rather than mere webpages. v45 introduces several other minor improvements to service workers that are oriented towards web developers rather than user-facing changes.
The Android version of Chrome Beta v45 should be rolling out any day now. Keep an eye on APK Mirror for the release if you're impatient.
- Chromium Blog