Support the new Buffer in cudf (#1033)

Support the new `Buffer` in rapidsai/cudf#12009

Fixes  #1032

Authors:
  - Mads R. B. Kristensen (https://github.com/madsbk)

Approvers:
  - Peter Andreas Entschev (https://github.com/pentschev)

URL: #1033

dask_cuda/get_device_memory_objects.py

@@ -51,8 +51,9 @@ def get_device_memory_objects_default(obj):
         return dispatch(obj._pxy_get().obj)
     if hasattr(obj, "data"):
         return dispatch(obj.data)
-    if hasattr(obj, "_owner") and obj._owner is not None:
-        return dispatch(obj._owner)
+    owner = getattr(obj, "owner", None) or getattr(obj, "_owner", None)
+    if owner:
+        return dispatch(owner)
     if hasattr(obj, "__cuda_array_interface__"):
         return [obj]
     return []

dask_cuda/tests/test_proxify_host_file.py

@@ -273,7 +273,7 @@ def test_dataframes_share_dev_mem():
     # Even though the two dataframe doesn't point to the same cudf.Buffer object
     assert view1["a"].data is not view2["a"].data
     # They still share the same underlying device memory
-    assert view1["a"].data._owner._owner is view2["a"].data._owner._owner
+    view1["a"].data.ptr == view2["a"].data.ptr
 
     dhf = ProxifyHostFile(
         local_directory=root_dir, device_memory_limit=160, memory_limit=1000