rtc::Bind: Capture method objects as scoped_refptr if they are ref counted

R=tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1300523004 .

Cr-Original-Commit-Position: refs/heads/master@{#9744}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: d3de9c548d1121e7c4787a4b81fd66be714abc04
3 files changed