This becomes necessary due to [1]. We cannot roll DEPS otherwise [2].
WebRTC is doing this too [3].

[1] https://chromium-review.googlesource.com/c/chromium/src/+/1500198
[2] https://chromium-review.googlesource.com/c/v8/v8/+/1505272
[3] https://webrtc-review.googlesource.com/c/src/+/125840

TBR=machenbach@chromium.org

Change-Id: I07ecc878f6c64767be025c9999dbb49423031e90
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1505292Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60046}