ViEExternalRendererImpl: Remove dependency to webrtc::VideoFrame

I had to use std::vector, because rtc::Buffer wasn't in rtc_base_approved.

R=mflodman@webrtc.org, pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/34249004

Cr-Commit-Position: refs/heads/master@{#8426}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8426 4adac7df-926f-26a2-2b94-8c16560cd09d
2 files changed