Reland "Remove old AppRTC download location."

This reverts commit b97bf3623fce3d2edbe0286e6013e4eb37ae9215.

Reason for revert: https://chromium-review.googlesource.com/c/chromium/src/+/1781684 is now landed.


Bug: chromium:997673
Change-Id: I5d1f688ac7743eab9dfa2e7e6e1bdcaf865dba18
Reviewed-on: https://webrtc-review.googlesource.com/c/webrtc.DEPS/+/151361
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>