Thanks for bringing this issue up @agarzia,
I think solving the general scrolling issue using innertia to trigger a fast scroll in either direction will be very useful almost everywhere, and we will need to reduce friction against asrolling. User can do a quick flick and watch the content pass by in a fraction of a second. If they want to stop it they can put their finger back on the screen. This will make the apps feel much faster as well, if implemented correctly.
I agree for the browser in particular, there can be a more elagant solution with additional touches. I also like the Firefox for Android way. But there are many apps, and many more reasons why user may need to quickly get to top or bottom of content. I dont think the above bug is enough to address the general case. Do we need to file another bug to improve scrolling overall? At least we need to come up with a guideline for scrolling so each app can improve their implementation, if this can not be solved in a central place. Ideally we would want to end up with a uniform implementation so user can scroll content the same way everywhere.