buffet: Remove DBusManager class

Move the TestMethod to the Manager, then remove the DBusManager
entirely.  This lets us turn the object at org/chromium/Buffet
into a pure object manager and removes a lot of boilerplate.

BUG=chromium:359190
TEST=buffet_client continues to demonstrate buffet functionality
through the TestMethod, which is now implementated by the Manager.

Change-Id: Ie9ecf0f7dd4dd50a3355ad7b06b8e2cfca71d9f9
Reviewed-on: https://chromium-review.googlesource.com/198760
Tested-by: Christopher Wiley <wiley@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/buffet/main.cc b/buffet/main.cc
index 6d8ddc2..e48a1b0 100644
--- a/buffet/main.cc
+++ b/buffet/main.cc
@@ -12,10 +12,10 @@
 #include <base/message_loop/message_loop.h>
 #include <base/strings/string_util.h>
 #include <base/strings/stringprintf.h>
+#include <dbus/bus.h>
 #include <sysexits.h>
 
 #include "buffet/async_event_sequencer.h"
-#include "buffet/dbus_manager.h"
 #include "buffet/manager.h"
 
 using buffet::dbus_utils::AsyncEventSequencer;
@@ -87,8 +87,6 @@
 void EnterMainLoop(base::MessageLoopForIO* message_loop,
                    scoped_refptr<dbus::Bus> bus) {
   scoped_refptr<AsyncEventSequencer> sequencer(new AsyncEventSequencer());
-  buffet::DBusManager dbus_manager(bus.get());
-  dbus_manager.Init(sequencer->GetHandler("DBusManager.Init() failed.", true));
   buffet::Manager manager(bus.get());
   manager.Init(sequencer->GetHandler("Manager.Init() failed.", true));
   sequencer->OnAllTasksCompletedCall(