libweave: Wrap ListValue& by ValueReferenceAdapter.

This is to prepare libchrome uprev.

BUG=b:37434548
TEST=Try.

Change-Id: I0492b8e3bebfabbf524627bc0317c32f4c26993b
Reviewed-on: https://chromium-review.googlesource.com/1263055
Commit-Ready: Hidehiko Abe <hidehiko@chromium.org>
Tested-by: Hidehiko Abe <hidehiko@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
3 files changed