buffet: Add an abstract command dispatch interface

Added simple framework for implementing command dispatch from
buffet to command-handling daemons which concrete delivery
layers, such as D-Bus, can use to actually implement the command
delivery.

Also changed some CommandQueue unit tests to remove the
implementation detail knowledge of how the command IDs are generated.

BUG=chromium:374864
TEST=USE=buffet P2_TEST_FILTER="buffet::*" FEATURES=test emerge-link platform2

Change-Id: Ic7a719a09e924fefedc72cc0bb675adf1acd3713
Reviewed-on: https://chromium-review.googlesource.com/211485
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
4 files changed
tree: 8d0eea24cf4d832e44d4cc516e1febac89c54142
  1. buffet/