This class is already just an alias for std::unique_ptr<T[]>, so replace
all uses with that and delete the class.
CQ_INCLUDE_TRYBOTS=master.client.skia:Test-Ubuntu-Clang-GCE-CPU-AVX2-x86_64-Debug-ASAN-Trybot,Test-Ubuntu-Clang-Golo-GPU-GT610-x86_64-Debug-ASAN-Trybot
Change-Id: I40668d398356a22da071ee791666c7f728b59266
Reviewed-on: https://skia-review.googlesource.com/4362
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>