Change weave::Device::Register API to async version

Implementation of this function is the only place using
HttpClient::SendRequestAndBlock.

BUG:24267885
Change-Id: I8ebd34537ce42214ce262795b940923f3b11da79
Reviewed-on: https://weave-review.googlesource.com/1279
Reviewed-by: Alex Vakulenko <avakulenko@google.com>
10 files changed
tree: 1f10cf1a1276d3cb7a659ef1c2891240c0f81a00
  1. libweave/