Further cleanup around DBus interface classes.

* Removed the "Glib" part from the various DbusGlib class name and added
  "Wrapper" instead: only part of the methods here declared have
  anything to do with Glib; in essence, this is an interface containing
  wrappers for various DBus functions.

* Changed "Dbus" to "DBus", to comply with the rest of the world.

* Renamed the actual implementation "RealDBusWrapper" (instead of
  "Concrete").

* Separated out RealDBusWrapper into its own header file. Client code,
  which often only cares about the abstract class, does not need to pull
  it unless specifically requiring it.

* Cleaned up the includes in these headers.

Aside from all that, also renamed system_state.cc into
real_system_state.cc, as this is what this file contains.

BUG=None
TEST=Unit tests.

Change-Id: I015c407cbc159aba8b5925eb0e916ba604c829cd
Reviewed-on: https://chromium-review.googlesource.com/189373
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/connection_manager.h b/connection_manager.h
index 6cc279e..58307ff 100644
--- a/connection_manager.h
+++ b/connection_manager.h
@@ -7,7 +7,7 @@
 
 #include <base/basictypes.h>
 
-#include "update_engine/dbus_interface.h"
+#include "update_engine/dbus_wrapper_interface.h"
 
 namespace chromeos_update_engine {
 
@@ -34,7 +34,7 @@
   // Populates |out_type| with the type of the network connection
   // that we are currently connected. The dbus_iface is used to
   // query the real connection manager (e.g shill).
-  virtual bool GetConnectionType(DbusGlibInterface* dbus_iface,
+  virtual bool GetConnectionType(DBusWrapperInterface* dbus_iface,
                                  NetworkConnectionType* out_type) const;
 
   // Returns true if we're allowed to update the system when we're