Changing include guard in frame_callback.h. R=pbos@webrtc.org Review URL: https://webrtc-codereview.appspot.com/39769004 Cr-Commit-Position: refs/heads/master@{#8233} git-svn-id: http://webrtc.googlecode.com/svn/trunk@8233 4adac7df-926f-26a2-2b94-8c16560cd09d