This makes the dependency graph simpler and prepares for moving the unit classes to api/. Bug: webrtc:9155 Change-Id: I1b36d5e05f75d70ba8951e880d76359f896f7741 Reviewed-on: https://webrtc-review.googlesource.com/74920 Reviewed-by: Björn Terelius <terelius@webrtc.org> Commit-Queue: Sebastian Jansson <srte@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23161}