dbus: Support UnexportMethod from an exported object.

Currently there is no way to override a method handler that is already
registered to an ExportedObject. A support to do so is required to
correctly implement Chrome OS Bluetooth dispatcher which needs to
add/remove an interface to an exported object dynamically. Therefore
this CL adds methods to allow method handlers to be unexported so
another handler can be exported afterwards.

Bug: 883039
Change-Id: Id26dbdb8b2ee3425c21ec0797e1c08183f3e04ab
Reviewed-on: https://chromium-review.googlesource.com/c/1370573
Commit-Queue: Sonny Sasaka <sonnysasaka@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616020}
3 files changed