Split video engine android initialization into each internal module initialization.
Split video engine android initialization into each internal module initialization.

This is to later on allow targets to pick at link time if to include the external or internal implementation. In order to do that the video_engine cannot compile different based on which option is picked later on.

BUG=3768,3770
R=glaznev@webrtc.org, stefan@webrtc.org
TBR=henrike@webrtc.org, mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/25529004

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 85ef770d92bb8b632bcdf73847c42c1461bd8922

sippet/talk,sippet/talk,sippet/talk,sippet/talk,sippet/talk