rtc::Bind: Capture scoped_refptr reference arguments by value

R=tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1308563004 .

Cr-Original-Commit-Position: refs/heads/master@{#9780}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: b274547ebdefd0db470e21cfe113457cabd99dff
3 files changed