Remove non-ARC code from the codebase.

BUG=webrtc:7198

Review-Url: https://codereview.webrtc.org/2702153004
Cr-Original-Commit-Position: refs/heads/master@{#16765}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: de6adbe0ba02a5a659db5f3abd809c668d146b69
4 files changed