chromeos: Fix interface nits.

chromeos/dbus/dbus_thread_manager_observer.h

Index: chromeos/dbus/dbus_thread_manager_observer.h
diff --git a/chromeos/dbus/dbus_thread_manager_observer.h b/chromeos/dbus/dbus_thread_manager_observer.h
index 57e54ffd39fc08ccc460f84731b942a4a8073123..77ce14f849f1282cc6e2edb5c41e98ae87a7ab6c 100644
--- a/chromeos/dbus/dbus_thread_manager_observer.h
+++ b/chromeos/dbus/dbus_thread_manager_observer.h
@@ -5,8 +5,6 @@
 #ifndef CHROMEOS_DBUS_DBUS_THREAD_MANAGER_OBSERVER_H_
 #define CHROMEOS_DBUS_DBUS_THREAD_MANAGER_OBSERVER_H_
 
-#include "base/basictypes.h"
-
 namespace chromeos {
 
 class DBusThreadManager;
@@ -15,15 +13,12 @@ class DBusThreadManager;
 // DBusThreadManager.
 class DBusThreadManagerObserver {
  public:
-  DBusThreadManagerObserver() {}
-  virtual ~DBusThreadManagerObserver() {}
-
   // Called when |manager| is about to be destroyed.  |manager| is still usable
   // at this point.
   virtual void OnDBusThreadManagerDestroying(DBusThreadManager* manager) = 0;
 
- private:
-  DISALLOW_COPY_AND_ASSIGN(DBusThreadManagerObserver);
+ protected:
+  virtual ~DBusThreadManagerObserver() {}
 };
 
 }  // namespace chromeos