[M66 merge] MD Extensions: Allow scrolling in options dialog.

This makes it possible for the user to reach extension provided options that
don't fit in the viewport.

TBR=dpapad@chromium.org

(cherry picked from commit d4912b2051e7f264221deacb9b7ecfbeadddee9d)

Bug: 820876
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: Idf3ef16f0cead1da99bf255b32b4669072518c19
Reviewed-on: https://chromium-review.googlesource.com/960968
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Scott Chen <scottchen@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#542910}
Reviewed-on: https://chromium-review.googlesource.com/969108
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/branch-heads/3359@{#307}
Cr-Branched-From: 66afc5e5d10127546cc4b98b9117aff588b5e66b-refs/heads/master@{#540276}
1 file changed