Add download_from_google_storage to win_cross.md

Change-Id: I2cec6dd278a7c89315998c87eb0f8f0d81569b78
Reviewed-on: https://chromium-review.googlesource.com/734282
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#510919}
1 file changed