exo: Fix private test deps for cast build

These dependencies were pulled via Ash test deps. Need to explicitly
depend on to build for Chromecast.

Bug: 896710
Test: "gn gen out/cast --check" to ensure there are no errors
Change-Id: Iaa51ddbc7f729a730a16e6837c22e2b57de0739b
Reviewed-on: https://chromium-review.googlesource.com/c/1341003
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Commit-Queue: Daniel Nicoara <dnicoara@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614103}
2 files changed