[ObjC ARC] Converts ios/chrome/browser/ui/overscroll_actions:overscroll_actions to ARC.

Automatically generated ARCMigrate commit
Notable issues:None
BUG=624363
TEST=None

Review-Url: https://codereview.chromium.org/2933123002
Cr-Commit-Position: refs/heads/master@{#478739}
5 files changed