Open sourced protos have additional lite_runtime optimization to avoid
depending on the full protobuf library which is heavier.
Change-Id: Ia4d96bcb792b56d0cae78142cd515f0d7fb3d006
This helps in using webrtc in other open source projects which might
have a different location for the webrtc headers.
Change-Id: Ifa9aea95a26fa542544d83343ef90144835960c3