libweave: Added TODO into header file BUG=none TEST=none Change-Id: I6ef5b3b92c3eae991a272674b4f4070226c6cd28 Reviewed-on: https://chromium-review.googlesource.com/296320 Reviewed-by: Vitaly Buka <vitalybuka@chromium.org> Commit-Queue: Vitaly Buka <vitalybuka@chromium.org> Tested-by: Vitaly Buka <vitalybuka@chromium.org>