Remove DISALLOW_ macro from include/ (see issue #3234)

Also perform related C++ cleanup:
- Use =default instead of {} for default implementations of
  constructors/destructors.
- Replace typedef with using.

include/base/cef_scoped_refptr.h

@@ -48,7 +48,6 @@
 
 #include "include/base/cef_compiler_specific.h"
 #include "include/base/cef_logging.h"
-#include "include/base/cef_macros.h"
 
 template <class T>
 class scoped_refptr;