Use MobileScroller instead of cloning it.

Chromecast wants to scroll exactly like Android and for that
the code cloned the mobile scrolling code, but simpler and
easier and with less code and fewer jumbo compilation errors
is to just use the existing code directly.

Only a minor code difference existed and that is controlled with
a conditional statement instead now.

Bug: 813911
Change-Id: I9d037da9b58c1ad0916dc22ee194328c113075cd
Reviewed-on: https://chromium-review.googlesource.com/1136541
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Kevin Schoedel <kpschoedel@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#576035}
8 files changed