Revert "Add a constant for GetFreeDiskSpace()."

This reverts commit c74bf51d2bc256adf09b6cfb2e353262fa43a736.

We decided to do disk space check in Chrome side for now, so this
change turned out not needed.

BUG=chromium:625923
BUG=b/30025308

Change-Id: I82854f75374135de2989af75329cb83ab58c8939
Reviewed-on: https://chromium-review.googlesource.com/362240
Commit-Ready: Shuhei Takahashi <nya@chromium.org>
Tested-by: Shuhei Takahashi <nya@chromium.org>
Reviewed-by: Darren Krahn <dkrahn@chromium.org>
1 file changed