Checkout APM and dependencies from upstream WebRTC Generate source code by command: ./script/sync-apm.sh ~/webrtc-checkout/src . where webrtc-checkout HEAD is at 8a1b20a21 BUG=chromium:710465 TEST=None Change-Id: Iceab82cf72dc4c0550c8864580ed9f75d4f9a596 Reviewed-on: https://chromium-review.googlesource.com/970197 Commit-Ready: Hsinyu Chao <hychao@chromium.org> Tested-by: Hsinyu Chao <hychao@chromium.org> Reviewed-by: Cheng-Yi Chiang <cychiang@chromium.org>