diagnostics: API for bootstrapping Mojo to browser

Add D-Bus API that allows bootstrapping Mojo connection between
browser and diagnosticsd. Mojo will be used for the actual
bidirectional communication between these two endpoints.

BUG=chromium:869377
TEST=none

Change-Id: I1746e26a95e5d8d04b47ffd7a54c29456c83de01
Reviewed-on: https://chromium-review.googlesource.com/1165982
Commit-Ready: Maksim Ivanov <emaxx@chromium.org>
Tested-by: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Dan Erat <derat@chromium.org>
2 files changed