Fix constants.[h|cc] to avoid static initializer in webrtcvideoengine.cc.

R=wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/5179004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/talk@5233 4adac7df-926f-26a2-2b94-8c16560cd09d
3 files changed