Route commands without path to suitable component

Use the trait name to find the first component that implements
that trait to send the command to.

BUG: 25917421
Change-Id: Ife284100fb7d0bf94416bf5ba2ab9b797076ce23
Reviewed-on: https://weave-review.googlesource.com/1783
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
3 files changed