  Mobile web browsing has recently surpassed desktop browsing both in term of
popularity and traffic. Following its desktop counterpart, the mobile browsers
ecosystem has been growing from few browsers (Chrome, Firefox, and Safari) to a
plethora of browsers, each with unique characteristics (battery friendly,
privacy preserving, lightweight, etc.). In this paper, we introduce a browser
benchmarking pipeline for Android browsers encompassing automation, in-depth
experimentation, and result analysis. We tested 15 Android browsers, using
Cappuccino a novel testing suite we built for third party Android applications.
We perform a battery-centric analysis of such browsers and show that: 1)
popular browsers tend also to consume the most, 2) adblocking produces
significant battery savings (between 20 and 40% depending on the browser), and
3) dark mode offers an extra 10% battery savings on AMOLED screens. We exploit
this observation to build AttentionDim, a screen dimming mechanism driven by
browser events. Via integration with the Brave browser and 10 volunteers, we
show potential battery savings up to 30%, on both devices with AMOLED and LCD
screens.
