The http://metadata shortcut only works on Linux, Windows requires
https://metadata.google.internal.

Bug: 738255
Change-Id: I06b6c34761bbee9912a8cd2a65ab43b3ae230f07
Reviewed-on: https://chromium-review.googlesource.com/611245Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: smut <smut@google.com>