Pipe the remaining time for an animation all the way out to the AnimatedValue.
Make splashes abortable, which causes them to continue to fade but no longer grow, by having them fade in 100ms or however long the animation was still going to go for, whichever is quickest.
Make Scrollables support objects registering with them to be told when scrolling happens.
Make UINode support subclasses being informed when _remove() was called.
Hook all that together to make splashes go away when scrolling by having them register with any ancestor Scrollables such that when those scroll, all the splashes get aborted. Unregister when removed.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/1092423003