Address comments from previous review round for rtc::Event.

R=andresp@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/35049004

Cr-Commit-Position: refs/heads/master@{#8313}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8313 4adac7df-926f-26a2-2b94-8c16560cd09d
2 files changed