update_engine: Switch to chrome-dbus for client requests in update_engine

update_engine daemon acts as DBus client to send DBus calls to shill,
power_manager and chrome, and to listen for signals from shill, chrome
and login_manager. This patch migrates these calls and signals to use
chrome-dbus framework instead of dbus-glib.

All references to dbus-glib code are removed.

BUG=chromium:419827
TEST=Updated unittest. Deployed on a link device and tested interactions with shill and chromium.

Change-Id: I31b389e0d1690cccb115ff3b6539c876ba81bd0e
Reviewed-on: https://chromium-review.googlesource.com/290990
Tested-by: Alex Deymo <deymo@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
Trybot-Ready: Alex Deymo <deymo@chromium.org>
diff --git a/update_engine_client.cc b/update_engine_client.cc
index d0fee7a..a2470f3 100644
--- a/update_engine_client.cc
+++ b/update_engine_client.cc
@@ -17,8 +17,8 @@
 #include <chromeos/flag_helper.h>
 #include <dbus/bus.h>
 
+#include "update_engine/client_dbus_proxies.h"
 #include "update_engine/dbus_constants.h"
-#include "update_engine/dbus_proxies.h"
 
 using chromeos_update_engine::kAttemptUpdateFlagNonInteractive;
 using chromeos_update_engine::kUpdateEngineServiceName;