Instrumented libraries: drop liboverlay-scrollbar.

Chrome doesn't use overlay scrollbars. The only thing that we do with this
library is attempt to initialize it (as part of gtk2+ init) which occasionally
tries to read a missing settings schema and crashes.

BUG=456205
TBR=glider@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/905703003

Cr-Original-Commit-Position: refs/heads/master@{#315361}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: fa52c8105b87d7e9963e9ca7a346575b0f0cf24c
3 files changed