object-group network DROPBOX_AS19679
 network-object 108.160.160.0 255.255.240.0
 network-object 199.47.216.0 255.255.252.0

!

access-list ACL_Dropbox extended permit ip object-group Inside object-group DROPBOX_AS19679
access-list ACL_Dropbox extended permit ip object-group DROPBOX_AS19679 object-group Inside
!

You would also need to define an object-group for your “Inside” address blocks

class-map Class_Dropbox
 match access-list ACL_Dropbox
!
policy-map Policy_Police
 class Class_Dropbox
  police input 384000
  police output 384000
 class class-default
!
service-policy Policy_Police interface INSIDE