GitLab

- Makes device::SendBuffer ctor take 'const std::vector<uint8_t>&'
  rather than 'const std::vector<char>&'
- Changes type of its member |data_| from 'const std::vector<char>' to
  'const std::vector<uint8_t>'.

BUG=749515
TBR=charliea@chromium.org

Change-Id: I27424642d866174be84f7916f260b1f5e6b769a8
Reviewed-on: https://chromium-review.googlesource.com/620207
Commit-Queue: Han Leon <leon.han@intel.com>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496571}