I just fixed an annoying bug where I accidentally used DataRange more
than once, leading to endless recursion.
This CL avoids that by forbidding copying of DataRange. Instead, it's
mostly passed by reference now.

R=ahaas@chromium.org
CC=eholk@chromium.org

Change-Id: I3925548951645d13823ff42d9d833bde76d6cca6
Reviewed-on: https://chromium-review.googlesource.com/839762
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50273}