[C++[ arrow::gpu::CudaContext::bytes_allocated() isn't defined

[asfimport]

arrow/gpu/cuda_context.h declares arrow::gpu::CudaContext::bytes_allocated() but it's not defined.
Should it be removed or defined?

CudaContext::CudaContextImple::bytes_allocated() exists. So it's easy to define it.

Reporter: Kouhei Sutou / @kou
Assignee: Kouhei Sutou / @kou

PRs and other links:

• GitHub Pull Request #1293

_{Note: This issue was originally created as ARROW-1776. Please see the migration documentation for further details.}

[asfimport]

Wes McKinney / @wesm:
Yes, it should be defined

[asfimport]

Uwe Korn / @xhochy:
Resolved by PR #1293