Implemented IScrollProvider, allowing for scrolling to accessible objects in UI automation

R=dmazzoni@chromium.org, aleventhal@chromium.org, suproteem@chromium.org

Bug: 856741
Change-Id: Ic7d7b5cd157ee579064e9427e8e0fa33571b770e
Reviewed-on: https://chromium-review.googlesource.com/1137259
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577049}
6 files changed